Update CHANGELOG for v0.3.10

* Save metadata on Sync

* Add test

.chglog/CHANGELOG.tpl.md

@@ -0,0 +1,22 @@
+{{ range .Versions }}
+<a name="{{ .Tag.Name }}"></a>
+## {{ if .Tag.Previous }}[{{ .Tag.Name }}]({{ $.Info.RepositoryURL }}/compare/{{ .Tag.Previous.Name }}...{{ .Tag.Name }}){{ else }}{{ .Tag.Name }}{{ end }} ({{ datetime "2006-01-02" .Tag.Date }})
+
+{{ range .CommitGroups -}}
+### {{ .Title }}
+
+{{ range .Commits -}}
+* {{ .Subject }}
+{{ end }}
+{{ end -}}
+
+{{- if .NoteGroups -}}
+{{ range .NoteGroups -}}
+### {{ .Title }}
+
+{{ range .Notes }}
+{{ .Body }}
+{{ end }}
+{{ end -}}
+{{ end -}}
+{{ end -}}

.chglog/config.yml

@@ -0,0 +1,28 @@
+---
+style: Github
+template: CHANGELOG.tpl.md
+info:
+  title: CHANGELOG
+  repository_url: https://github.com/prologic/bitcask
+options:
+  commits:
+    filters:
+      Type:
+        - Add
+        - Fix
+        - Update
+        - Document
+  commit_groups:
+    title_maps:
+      Add: Features
+      Update: Updates
+      Fix: Bug Fixes
+      Document: Documentation
+  header:
+    pattern: "^((\\w+)\\s.*)$"
+    pattern_maps:
+      - Subject
+      - Type
+  notes:
+    keywords:
+      - BREAKING CHANGE

.dependabot/config.yml

@@ -0,0 +1,8 @@
+version: 1
+update_configs:
+  - package_manager: "go:modules"
+    directory: "/"
+    update_schedule: "daily"
+  - package_manager: "docker"
+    directory: "/"
+    update_schedule: "weekly"

.drone.yml

@@ -1,14 +0,0 @@
-kind: pipeline
-name: default
-
-steps:
-  - name: build
-    image: golang:latest
-    commands:
-      - go test -v -cover -coverprofile=coverage.txt -covermode=atomic -coverpkg=$(shell go list) -race .
-
-  - name: coverage
-    image: plugins/codecov
-    settings:
-      token:
-        from_secret: codecov-token

.github/labeler.yml

@@ -0,0 +1,9 @@
+documentation:
+  - "**/*.md"
+
+tests:
+  - "**/*_test.go"
+
+dependencies:
+  - go.mod
+  - go.sum

.github/workflows/codecov.yml

@@ -0,0 +1,23 @@
+name: Coverage
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+jobs:
+  test:
+    name: Test and Report
+    runs-on: ubuntu-latest
+    steps:
+      - name: Setup Go
+        uses: actions/setup-go@v1
+        with:
+          go-version: 1.13.x
+      - name: Checkout
+        uses: actions/checkout@v1
+      - name: Test
+        run: go test -v -cover -coverprofile=coverage.txt -covermode=atomic -race .
+      - name: Report
+        uses: codecov/codecov-action@v1
+        with:
+          token: ${{ secrets.CODECOV_TOKEN }}

.github/workflows/docker.yml

@@ -0,0 +1,15 @@
+name: Docker
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+jobs:
+  build:
+    name: Build Image
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v1
+      - name: Build
+        run: docker build -t bitcask .

.github/workflows/go.yml

@@ -0,0 +1,27 @@
+---
+name: Go
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+jobs:
+  test:
+    name: Build and Test
+    strategy:
+      matrix:
+        go-version: [1.12.x, 1.13.x, 1.14.x, 1.15.x]
+        platform: [ubuntu-latest, macos-latest]
+    runs-on: ${{ matrix.platform }}
+    steps:
+      - name: Setup Go ${{ matrix.go-version }}
+        uses: actions/setup-go@v2
+        with:
+          go-version: ${{ matrix.go-version }}
+        id: go
+      - name: Checkout
+        uses: actions/checkout@v1
+      - name: Build
+        run: go build -v .
+      - name: Test
+        run: go test -v -race .

.github/workflows/reviewdog.yml

@@ -0,0 +1,32 @@
+name: ReviewDog
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+jobs:
+  golangci-lint:
+    name: runner / golangci-lint
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v1
+      - uses: reviewdog/action-golangci-lint@v1
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+  misspell:
+      name: runner / misspell
+      runs-on: ubuntu-latest
+      steps:
+        - uses: actions/checkout@v1
+        - uses: reviewdog/action-misspell@v1
+          with:
+            github_token: ${{ secrets.GItHUB_TOKEN }}
+  shellcheck:
+      name: runner / shellcheck
+      runs-on: ubuntu-latest
+      steps:
+        - uses: actions/checkout@v1
+        - uses: reviewdog/action-shellcheck@v1
+          with:
+            github_token: ${{ secrets.GITHUB_TOKEN }}
+            reporter: github-pr-review

.github/workflows/stale.yml

@@ -0,0 +1,29 @@
+name: Mark stale issues and pull requests
+
+on:
+  schedule:
+  - cron: "0 0 * * *"
+
+jobs:
+  stale:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/stale@v1
+      with:
+        repo-token: ${{ secrets.GITHUB_TOKEN }}
+        stale-issue-message: |-
+          This Issue has gone stale and will be closed automatically.
+          
+          If this is incorrect, please reopen and add the label `on hold`.
+          
+          Thank you.
+        stale-pr-message: |-
+          This Pull Request has gone stale and will be closed automatically.
+          
+          If this is incorrect, please reopen and add the label `on hold`.
+          
+          Thank you.
+        stale-issue-label: 'stale'
+        exempt-issue-label: 'on hold'
+        stale-pr-label: 'stale'
+        exempt-pr-label: 'on hold'

.gitignore

@@ -2,8 +2,12 @@
 *.bak
 *.db
 
-/coverage.txt
-/bitcask
-/bitcaskd
 /tmp
 /dist
+/coverage.txt
+
+/bitcask
+/bitcaskd
+/bitcask_bench*
+/cmd/bitcask/bitcask
+/cmd/bitcaskd/bitcaskd

.goreleaser.yml

@@ -1,34 +1,25 @@
+---
 builds:
-  - 
+  -
+    id: bitcask
     binary: bitcask
     main: ./cmd/bitcask
     flags: -tags "static_build"
     ldflags: -w -X github.com/prologic/bitcask/internal.Version={{.Version}} -X github.com/prologic/bitcask/internal.Commit={{.Commit}}
     env:
       - CGO_ENABLED=0
-  - 
+  -
+    id: bitcaskd
     binary: bitcaskd
     main: ./cmd/bitcaskd
     flags: -tags "static_build"
     ldflags: -w -X github.com/prologic/bitcask/internal.Version={{.Version}} -X github.com/prologic/bitcask/internal.Commit={{.Commit}}
     env:
       - CGO_ENABLED=0
-sign:
-  artifacts: checksum
-archive:
-  replacements:
-    darwin: Darwin
-    linux: Linux
-    windows: Windows
-    386: i386
-    amd64: x86_64
-checksum:
-  name_template: 'checksums.txt'
-snapshot:
-  name_template: "{{ .Tag }}-next"
-changelog:
-  sort: asc
-  filters:
-    exclude:
-    - '^docs:'
-    - '^test:'
+signs:
+  - artifacts: checksum
+release:
+  github:
+    owner: prologic
+    name: bitcask
+  draft: true

AUTHORS

@@ -2,12 +2,17 @@
 #   Name or Organization <email address>
 # The email address is not required for organizations.
 
+Alain Gilbert <alain.gilbert.15@gmail.com>
 Awn Umar <awn@spacetime.dev>
+Bryan Stenson <bryan@siliconvortex.com>
 Christian Muehlhaeuser <muesli@gmail.com>
 Ignacio Hagopian <jsign.uy@gmail.com>
 James Mills <prologic@shortcircuit.net.au>
 Jesse Donat <donatj@gmail.com>
 Kebert Xela kebertxela
 panyun panyun 
+shiniao <zhuzhezhe95@gmail.com>
 Whemoon Jang <palindrom615@gmail.com>
 Yury Fedorov orlangure
+o2gy84 <o2gy84@gmail.com>
+garsue <labs.garsue@gmail.com>

CHANGELOG.md

@@ -0,0 +1,394 @@
+
+<a name="v0.3.10"></a>
+## [v0.3.10](https://github.com/prologic/bitcask/compare/v0.3.9...v0.3.10) (2020-12-18)
+
+### Bug Fixes
+
+* Fix a bug when MaxValueSize == 0 on Merge operations
+* Fix link to bitcask-bench
+* Fix CI (again)
+* Fix CI
+
+### Features
+
+* Add support for unlimited key/value sizes
+* Add a few more test cases for concurrent operations
+
+### Updates
+
+* Update README.md
+
+
+<a name="v0.3.9"></a>
+## [v0.3.9](https://github.com/prologic/bitcask/compare/v0.3.8...v0.3.9) (2020-11-17)
+
+### Bug Fixes
+
+* Fix a race condition around .Close() and .Sync()
+
+### Updates
+
+* Update CHANGELOG for v0.3.9
+
+
+<a name="v0.3.8"></a>
+## [v0.3.8](https://github.com/prologic/bitcask/compare/v0.3.7...v0.3.8) (2020-11-17)
+
+### Updates
+
+* Update CHANGELOG for v0.3.8
+
+
+<a name="v0.3.7"></a>
+## [v0.3.7](https://github.com/prologic/bitcask/compare/v0.3.6...v0.3.7) (2020-11-17)
+
+### Updates
+
+* Update CHANGELOG for v0.3.7
+
+
+<a name="v0.3.6"></a>
+## [v0.3.6](https://github.com/prologic/bitcask/compare/v0.3.5...v0.3.6) (2020-11-17)
+
+### Bug Fixes
+
+* Fix typo in labeler ([#172](https://github.com/prologic/bitcask/issues/172))
+* Fix builds configuration for goreleaser
+* Fix (again) goreleaser config
+* Fix goreleaser config and improve release notes / changelog
+* Fix recoverDatafile error covering ([#162](https://github.com/prologic/bitcask/issues/162))
+* Fix loadIndex to be deterministic ([#115](https://github.com/prologic/bitcask/issues/115))
+
+### Features
+
+* Add configuration options for FileMode ([#183](https://github.com/prologic/bitcask/issues/183))
+* Add imports and log in example code ([#182](https://github.com/prologic/bitcask/issues/182))
+* Add empty changelog
+* Add DependaBot config
+* Add DeleteAll function ([#116](https://github.com/prologic/bitcask/issues/116))
+
+### Updates
+
+* Update CHANGELOG for v0.3.6
+* Update README.md
+* Update CHANGELOG for v0.3.6
+* Update CHANGELOG for v0.3.6
+* Update deps ([#140](https://github.com/prologic/bitcask/issues/140))
+* Update README.md
+
+
+<a name="v0.3.5"></a>
+## [v0.3.5](https://github.com/prologic/bitcask/compare/v0.3.4...v0.3.5) (2019-10-20)
+
+### Bug Fixes
+
+* Fix setup target in Makefile to install mockery correctly
+* Fix glfmt/golint issues
+* Fix spelling mistake in README s/Sponser/Sponsor
+
+### Features
+
+* Add *.db to ignore future accidental commits of a bitcask db to the repo
+* Add unit test for opening bad database with corrupted/invalid datafiles ([#105](https://github.com/prologic/bitcask/issues/105))
+
+### Updates
+
+* Update Drone CI test pipeline
+* Update README.md
+* Update to Go 1.13 and update README with new benchmarks ([#89](https://github.com/prologic/bitcask/issues/89))
+* Update README.md
+
+
+<a name="v0.3.4"></a>
+## [v0.3.4](https://github.com/prologic/bitcask/compare/v0.3.3...v0.3.4) (2019-09-02)
+
+
+<a name="v0.3.3"></a>
+## [v0.3.3](https://github.com/prologic/bitcask/compare/v0.3.2...v0.3.3) (2019-09-02)
+
+### Bug Fixes
+
+* Fix a bug wit the decoder passing the wrong value for the value's offset into the buffer ([#77](https://github.com/prologic/bitcask/issues/77))
+* Fix typo ([#65](https://github.com/prologic/bitcask/issues/65))
+* Fix and cleanup some unnecessary internal sub-packages and duplication
+
+### Updates
+
+* Update README.md
+* Update README.md
+* Update README.md
+* Update README.md
+
+
+<a name="v0.3.2"></a>
+## [v0.3.2](https://github.com/prologic/bitcask/compare/v0.3.1...v0.3.2) (2019-08-08)
+
+### Updates
+
+* Update README.md
+* Update README.md
+* Update CONTRIBUTING.md
+
+
+<a name="v0.3.1"></a>
+## [v0.3.1](https://github.com/prologic/bitcask/compare/v0.3.0...v0.3.1) (2019-08-05)
+
+### Updates
+
+* Update README.md
+* Update README.md
+* Update README.md
+
+
+<a name="v0.3.0"></a>
+## [v0.3.0](https://github.com/prologic/bitcask/compare/v0.2.2...v0.3.0) (2019-07-29)
+
+### Updates
+
+* Update README.md
+* Update README.md
+
+
+<a name="v0.2.2"></a>
+## [v0.2.2](https://github.com/prologic/bitcask/compare/v0.2.1...v0.2.2) (2019-07-27)
+
+
+<a name="v0.2.1"></a>
+## [v0.2.1](https://github.com/prologic/bitcask/compare/v0.2.0...v0.2.1) (2019-07-25)
+
+
+<a name="v0.2.0"></a>
+## [v0.2.0](https://github.com/prologic/bitcask/compare/v0.1.7...v0.2.0) (2019-07-25)
+
+### Bug Fixes
+
+* Fix issue(db file Merge issue in windows env): ([#15](https://github.com/prologic/bitcask/issues/15))
+
+
+<a name="v0.1.7"></a>
+## [v0.1.7](https://github.com/prologic/bitcask/compare/v0.1.6...v0.1.7) (2019-07-19)
+
+### Bug Fixes
+
+* Fix mismatched key casing. ([#12](https://github.com/prologic/bitcask/issues/12))
+* Fix outdated README ([#11](https://github.com/prologic/bitcask/issues/11))
+* Fix typos in bitcask.go docs ([#10](https://github.com/prologic/bitcask/issues/10))
+
+### Updates
+
+* Update generated protobuf code
+* Update README.md
+
+
+<a name="v0.1.6"></a>
+## [v0.1.6](https://github.com/prologic/bitcask/compare/v0.1.5...v0.1.6) (2019-04-01)
+
+### Features
+
+* Add Development section to README documenting use of Protobuf and tooling required. [#6](https://github.com/prologic/bitcask/issues/6)
+* Add other badges from img.shields.io
+
+
+<a name="v0.1.5"></a>
+## [v0.1.5](https://github.com/prologic/bitcask/compare/v0.1.4...v0.1.5) (2019-03-30)
+
+### Documentation
+
+* Document using the Docker Image
+
+### Features
+
+* Add Dockerfile to publish images to Docker Hub
+
+### Updates
+
+* Update README.md
+
+
+<a name="v0.1.4"></a>
+## [v0.1.4](https://github.com/prologic/bitcask/compare/v0.1.3...v0.1.4) (2019-03-23)
+
+
+<a name="v0.1.3"></a>
+## [v0.1.3](https://github.com/prologic/bitcask/compare/v0.1.2...v0.1.3) (2019-03-23)
+
+
+<a name="v0.1.2"></a>
+## [v0.1.2](https://github.com/prologic/bitcask/compare/v0.1.1...v0.1.2) (2019-03-22)
+
+
+<a name="v0.1.1"></a>
+## [v0.1.1](https://github.com/prologic/bitcask/compare/v0.1.0...v0.1.1) (2019-03-22)
+
+
+<a name="v0.1.0"></a>
+## [v0.1.0](https://github.com/prologic/bitcask/compare/0.0.26...v0.1.0) (2019-03-22)
+
+
+<a name="0.0.26"></a>
+## [0.0.26](https://github.com/prologic/bitcask/compare/0.0.25...0.0.26) (2019-03-21)
+
+### Features
+
+* Add docs for bitcask
+* Add docs for options
+* Add KeYS command to server (bitraftd)
+* Add Len() to exported API (extended API)
+* Add Keys() to exported API (extended API)
+* Add EXISTS command to server (bitraftd)
+
+
+<a name="0.0.25"></a>
+## [0.0.25](https://github.com/prologic/bitcask/compare/0.0.24...0.0.25) (2019-03-21)
+
+### Features
+
+* Add Has() to exported API (extended API)
+* Add MergeOpen test case
+
+### Updates
+
+* Update README.md
+* Update README.md
+
+
+<a name="0.0.24"></a>
+## [0.0.24](https://github.com/prologic/bitcask/compare/0.0.23...0.0.24) (2019-03-20)
+
+
+<a name="0.0.23"></a>
+## [0.0.23](https://github.com/prologic/bitcask/compare/0.0.22...0.0.23) (2019-03-20)
+
+### Features
+
+* Add bitcaskd to install target
+
+
+<a name="0.0.22"></a>
+## [0.0.22](https://github.com/prologic/bitcask/compare/0.0.21...0.0.22) (2019-03-18)
+
+
+<a name="0.0.21"></a>
+## [0.0.21](https://github.com/prologic/bitcask/compare/0.0.20...0.0.21) (2019-03-18)
+
+
+<a name="0.0.20"></a>
+## [0.0.20](https://github.com/prologic/bitcask/compare/0.0.19...0.0.20) (2019-03-17)
+
+
+<a name="0.0.19"></a>
+## [0.0.19](https://github.com/prologic/bitcask/compare/0.0.18...0.0.19) (2019-03-17)
+
+
+<a name="0.0.18"></a>
+## [0.0.18](https://github.com/prologic/bitcask/compare/0.0.17...0.0.18) (2019-03-16)
+
+
+<a name="0.0.17"></a>
+## [0.0.17](https://github.com/prologic/bitcask/compare/0.0.16...0.0.17) (2019-03-16)
+
+### Features
+
+* Add CRC Checksum checks on reading values back
+
+
+<a name="0.0.16"></a>
+## [0.0.16](https://github.com/prologic/bitcask/compare/0.0.15...0.0.16) (2019-03-16)
+
+
+<a name="0.0.15"></a>
+## [0.0.15](https://github.com/prologic/bitcask/compare/0.0.14...0.0.15) (2019-03-16)
+
+### Bug Fixes
+
+* Fix a race condition + Use my fork of trie
+
+
+<a name="0.0.14"></a>
+## [0.0.14](https://github.com/prologic/bitcask/compare/0.0.13...0.0.14) (2019-03-16)
+
+
+<a name="0.0.13"></a>
+## [0.0.13](https://github.com/prologic/bitcask/compare/0.0.12...0.0.13) (2019-03-16)
+
+### Features
+
+* Add prefix scan for keys using a Trie
+
+
+<a name="0.0.12"></a>
+## [0.0.12](https://github.com/prologic/bitcask/compare/0.0.11...0.0.12) (2019-03-14)
+
+
+<a name="0.0.11"></a>
+## [0.0.11](https://github.com/prologic/bitcask/compare/0.0.10...0.0.11) (2019-03-14)
+
+### Updates
+
+* Update README.md
+
+
+<a name="0.0.10"></a>
+## [0.0.10](https://github.com/prologic/bitcask/compare/0.0.9...0.0.10) (2019-03-14)
+
+### Bug Fixes
+
+* Fix concurrent read bug
+* Fix concurrent write bug with multiple goroutines writing to the to the active datafile
+
+### Updates
+
+* Update README.md
+
+
+<a name="0.0.9"></a>
+## [0.0.9](https://github.com/prologic/bitcask/compare/0.0.8...0.0.9) (2019-03-14)
+
+
+<a name="0.0.8"></a>
+## [0.0.8](https://github.com/prologic/bitcask/compare/0.0.7...0.0.8) (2019-03-13)
+
+
+<a name="0.0.7"></a>
+## [0.0.7](https://github.com/prologic/bitcask/compare/0.0.6...0.0.7) (2019-03-13)
+
+
+<a name="0.0.6"></a>
+## [0.0.6](https://github.com/prologic/bitcask/compare/0.0.5...0.0.6) (2019-03-13)
+
+### Bug Fixes
+
+* Fix usage output of bitcaskd
+
+
+<a name="0.0.5"></a>
+## [0.0.5](https://github.com/prologic/bitcask/compare/0.0.4...0.0.5) (2019-03-13)
+
+### Features
+
+* Add a simple Redis compatible server daemon (bitcaskd)
+
+### Updates
+
+* Update README.md
+
+
+<a name="0.0.4"></a>
+## [0.0.4](https://github.com/prologic/bitcask/compare/0.0.3...0.0.4) (2019-03-13)
+
+### Features
+
+* Add flock on database Open()/Close() to prevent multiple concurrent processes write access. Fixes [#2](https://github.com/prologic/bitcask/issues/2)
+
+
+<a name="0.0.3"></a>
+## [0.0.3](https://github.com/prologic/bitcask/compare/0.0.2...0.0.3) (2019-03-13)
+
+
+<a name="0.0.2"></a>
+## [0.0.2](https://github.com/prologic/bitcask/compare/0.0.1...0.0.2) (2019-03-13)
+
+
+<a name="0.0.1"></a>
+## 0.0.1 (2019-03-13)
+

README.md

@@ -1,12 +1,17 @@
 # bitcask
 
-[![Build Status](https://cloud.drone.io/api/badges/prologic/bitcask/status.svg)](https://cloud.drone.io/prologic/bitcask)
+![](https://github.com/prologic/bitcask/workflows/Coverage/badge.svg)
+![](https://github.com/prologic/bitcask/workflows/Docker/badge.svg)
+![](https://github.com/prologic/bitcask/workflows/Go/badge.svg)
+![](https://github.com/prologic/bitcask/workflows/ReviewDog/badge.svg)
+
 [![CodeCov](https://codecov.io/gh/prologic/bitcask/branch/master/graph/badge.svg)](https://codecov.io/gh/prologic/bitcask)
 [![Go Report Card](https://goreportcard.com/badge/prologic/bitcask)](https://goreportcard.com/report/prologic/bitcask)
 [![codebeat badge](https://codebeat.co/badges/15fba8a5-3044-4f40-936f-9e0f5d5d1fd9)](https://codebeat.co/projects/github-com-prologic-bitcask-master)
 [![GoDoc](https://godoc.org/github.com/prologic/bitcask?status.svg)](https://godoc.org/github.com/prologic/bitcask) 
 [![GitHub license](https://img.shields.io/github/license/prologic/bitcask.svg)](https://github.com/prologic/bitcask)
 [![Sourcegraph](https://sourcegraph.com/github.com/prologic/bitcask/-/badge.svg)](https://sourcegraph.com/github.com/prologic/bitcask?badge)
+[![TODOs](https://img.shields.io/endpoint?url=https://api.tickgit.com/badge?repo=github.com/prologic/bitcask)](https://www.tickgit.com/browse?repo=github.com/prologic/bitcask)
 
 A high performance Key/Value store written in [Go](https://golang.org) with a predictable read/write performance and high throughput. Uses a [Bitcask](https://en.wikipedia.org/wiki/Bitcask) on-disk layout (LSM+WAL) similar to [Riak](https://riak.com/)
 
@@ -23,14 +28,14 @@ For a more feature-complete Redis-compatible server, distributed key/value store
 
 ## Development
 
-```#!sh
+```sh
 $ git clone https://github.com/prologic/bitcask.git
 $ make
 ```
 
 ## Install
 
-```#!sh
+```sh
 $ go get github.com/prologic/bitcask
 ```
 
@@ -38,20 +43,24 @@ $ go get github.com/prologic/bitcask
 
 Install the package into your project:
 
-```#!sh
+```sh
 $ go get github.com/prologic/bitcask
 ```
 
-```#!go
+```go
 package main
 
-import "github.com/prologic/bitcask"
+import (
+	"log"
+	"github.com/prologic/bitcask"
+)
 
 func main() {
     db, _ := bitcask.Open("/tmp/db")
     defer db.Close()
     db.Put([]byte("Hello"), []byte("World"))
     val, _ := db.Get([]byte("Hello"))
+    log.Printf(string(val))
 }
 ```
 
@@ -60,7 +69,7 @@ documentation and other examples.
 
 ## Usage (tool)
 
-```#!sh
+```sh
 $ bitcask -p /tmp/db set Hello World
 $ bitcask -p /tmp/db get Hello
 World
@@ -70,14 +79,14 @@ World
 
 There is also a builtin very  simple Redis-compatible server called `bitcaskd`:
 
-```#!sh
+```sh
 $ ./bitcaskd ./tmp
 INFO[0000] starting bitcaskd v0.0.7@146f777              bind=":6379" path=./tmp
 ```
 
 Example session:
 
-```#!sh
+```sh
 $ telnet localhost 6379
 Trying ::1...
 Connected to localhost.
@@ -102,7 +111,7 @@ Connection closed by foreign host.
 
 You can also use the [Bitcask Docker Image](https://cloud.docker.com/u/prologic/repository/docker/prologic/bitcask):
 
-```#!sh
+```sh
 $ docker pull prologic/bitcask
 $ docker run -d -p 6379:6379 prologic/bitcask
 ```
@@ -111,7 +120,7 @@ $ docker run -d -p 6379:6379 prologic/bitcask
 
 Benchmarks run on a 11" Macbook with a 1.4Ghz Intel Core i7:
 
-```#!sh
+```sh
 $ make bench
 ...
 goos: darwin
@@ -158,10 +167,6 @@ For 128B values:
 
 The full benchmark above shows linear performance as you increase key/value sizes.
 
-## Stargazers over time
-
-[![Stargazers over time](https://starcharts.herokuapp.com/prologic/bitcask.svg)](https://starcharts.herokuapp.com/prologic/bitcask)
-
 ## Support
 
 Support the ongoing development of Bitcask!
@@ -170,12 +175,31 @@ Support the ongoing development of Bitcask!
 
 - Become a [Sponsor](https://www.patreon.com/prologic)
 
+## Stargazers over time
+
+[![Stargazers over time](https://starcharts.herokuapp.com/prologic/bitcask.svg)](https://starcharts.herokuapp.com/prologic/bitcask)
+
 ## Contributors
 
 Thank you to all those that have contributed to this project, battle-tested it, used it in their own projects or products, fixed bugs, improved performance and even fix tiny typos in documentation! Thank you and keep contributing!
 
 You can find an [AUTHORS](/AUTHORS) file where we keep a list of contributors to the project. If you contriibute a PR please consider adding your name there. There is also Github's own [Contributors](https://github.com/prologic/bitcask/graphs/contributors) statistics.
 
+[![](https://sourcerer.io/fame/prologic/prologic/bitcask/images/0)](https://sourcerer.io/fame/prologic/prologic/bitcask/links/0)
+[![](https://sourcerer.io/fame/prologic/prologic/bitcask/images/1)](https://sourcerer.io/fame/prologic/prologic/bitcask/links/1)
+[![](https://sourcerer.io/fame/prologic/prologic/bitcask/images/2)](https://sourcerer.io/fame/prologic/prologic/bitcask/links/2)
+[![](https://sourcerer.io/fame/prologic/prologic/bitcask/images/3)](https://sourcerer.io/fame/prologic/prologic/bitcask/links/3)
+[![](https://sourcerer.io/fame/prologic/prologic/bitcask/images/4)](https://sourcerer.io/fame/prologic/prologic/bitcask/links/4)
+[![](https://sourcerer.io/fame/prologic/prologic/bitcask/images/5)](https://sourcerer.io/fame/prologic/prologic/bitcask/links/5)
+[![](https://sourcerer.io/fame/prologic/prologic/bitcask/images/6)](https://sourcerer.io/fame/prologic/prologic/bitcask/links/6)
+[![](https://sourcerer.io/fame/prologic/prologic/bitcask/images/7)](https://sourcerer.io/fame/prologic/prologic/bitcask/links/7)
+
+## Related Projects
+
+- [bitraft](https://github.com/prologic/bitraft) -- A Distributed Key/Value store (_using Raft_) with a Redis compatible protocol.
+- [bitcaskfs](https://github.com/prologic/bitcaskfs) -- A FUSE filesystem for mounting a Bitcask database.
+- [bitcask-bench](https://github.com/prologic/bitcask-bench) -- A benchmarking tool comparing Bitcask and several other Go key/value libraries.
+
 ## License
 
 bitcask is licensed under the term of the [MIT License](https://github.com/prologic/bitcask/blob/master/LICENSE)

bitcask.go

@@ -2,20 +2,24 @@ package bitcask
 
 import (
 	"errors"
+	"fmt"
 	"hash/crc32"
 	"io"
 	"io/ioutil"
 	"os"
 	"path"
 	"path/filepath"
+	"sort"
 	"sync"
 
-	"github.com/gofrs/flock"
 	art "github.com/plar/go-adaptive-radix-tree"
+	"github.com/prologic/bitcask/flock"
 	"github.com/prologic/bitcask/internal"
 	"github.com/prologic/bitcask/internal/config"
 	"github.com/prologic/bitcask/internal/data"
+	"github.com/prologic/bitcask/internal/data/codec"
 	"github.com/prologic/bitcask/internal/index"
+	"github.com/prologic/bitcask/internal/metadata"
 )
 
 var (
@@ -26,6 +30,9 @@ var (
 	// maximum allowed key size (configured with WithMaxKeySize).
 	ErrKeyTooLarge = errors.New("error: key too large")
 
+	// ErrEmptyKey is the error returned for a value with an empty key.
+	ErrEmptyKey = errors.New("error: empty key")
+
 	// ErrValueTooLarge is the error returned for a value that exceeds the
 	// maximum allowed value size (configured with WithMaxValueSize).
 	ErrValueTooLarge = errors.New("error: value too large")
@@ -37,6 +44,10 @@ var (
 	// ErrDatabaseLocked is the error returned if the database is locked
 	// (typically opened by another process)
 	ErrDatabaseLocked = errors.New("error: database locked")
+
+	// ErrMergeInProgress is the error returned if merge is called when already a merge
+	// is in progress
+	ErrMergeInProgress = errors.New("error: merge already in progress")
 )
 
 // Bitcask is a struct that represents a on-disk LSM and WAL data structure
@@ -54,6 +65,8 @@ type Bitcask struct {
 	datafiles map[int]data.Datafile
 	trie      art.Tree
 	indexer   index.Indexer
+	metadata  *metadata.MetaData
+	isMerging bool
 }
 
 // Stats is a struct returned by Stats() on an open Bitcask instance
@@ -82,12 +95,20 @@ func (b *Bitcask) Stats() (stats Stats, err error) {
 // Close() as this is the only way to cleanup the lock held by the open
 // database.
 func (b *Bitcask) Close() error {
-	defer func() {
-		b.Flock.Unlock()
-		os.Remove(b.Flock.Path())
-	}()
+	b.mu.RLock()
+	defer b.mu.RUnlock()
 
-	if err := b.indexer.Save(b.trie, filepath.Join(b.path, "index")); err != nil {
+	return b.close()
+}
+
+func (b *Bitcask) close() error {
+	defer b.Flock.Unlock()
+	if err := b.saveIndex(); err != nil {
+		return err
+	}
+
+	b.metadata.IndexUpToDate = true
+	if err := b.saveMetadata(); err != nil {
 		return err
 	}
 
@@ -102,18 +123,31 @@ func (b *Bitcask) Close() error {
 
 // Sync flushes all buffers to disk ensuring all data is written
 func (b *Bitcask) Sync() error {
+	b.mu.RLock()
+	defer b.mu.RUnlock()
+
+	if err := b.saveMetadata(); err != nil {
+		return err
+	}
+
 	return b.curr.Sync()
 }
 
-// Get retrieves the value of the given key. If the key is not found or an/I/O
-// error occurs a null byte slice is returned along with the error.
+// Get fetches value for given key
 func (b *Bitcask) Get(key []byte) ([]byte, error) {
+	b.mu.RLock()
+	defer b.mu.RUnlock()
+
+	return b.get(key)
+}
+
+// get retrieves the value of the given key. If the key is not found or an/I/O
+// error occurs a null byte slice is returned along with the error.
+func (b *Bitcask) get(key []byte) ([]byte, error) {
 	var df data.Datafile
 
-	b.mu.RLock()
 	value, found := b.trie.Search(key)
 	if !found {
-		b.mu.RUnlock()
 		return nil, ErrKeyNotFound
 	}
 
@@ -126,7 +160,6 @@ func (b *Bitcask) Get(key []byte) ([]byte, error) {
 	}
 
 	e, err := df.ReadAt(item.Offset, item.Size)
-	b.mu.RUnlock()
 	if err != nil {
 		return nil, err
 	}
@@ -149,30 +182,38 @@ func (b *Bitcask) Has(key []byte) bool {
 
 // Put stores the key and value in the database.
 func (b *Bitcask) Put(key, value []byte) error {
-	if uint32(len(key)) > b.config.MaxKeySize {
+	if len(key) == 0 {
+		return ErrEmptyKey
+	}
+	if b.config.MaxKeySize > 0 && uint32(len(key)) > b.config.MaxKeySize {
 		return ErrKeyTooLarge
 	}
-	if uint64(len(value)) > b.config.MaxValueSize {
+	if b.config.MaxValueSize > 0 && uint64(len(value)) > b.config.MaxValueSize {
 		return ErrValueTooLarge
 	}
 
 	b.mu.Lock()
+	defer b.mu.Unlock()
 	offset, n, err := b.put(key, value)
 	if err != nil {
-		b.mu.Unlock()
 		return err
 	}
 
 	if b.config.Sync {
 		if err := b.curr.Sync(); err != nil {
-			b.mu.Unlock()
 			return err
 		}
 	}
 
+	// in case of successful `put`, IndexUpToDate will be always be false
+	b.metadata.IndexUpToDate = false
+
+	if oldItem, found := b.trie.Search(key); found {
+		b.metadata.ReclaimableSpace += oldItem.(internal.Item).Size
+	}
+
 	item := internal.Item{FileID: b.curr.FileID(), Offset: offset, Size: n}
 	b.trie.Insert(key, item)
-	b.mu.Unlock()
 
 	return nil
 }
@@ -186,12 +227,34 @@ func (b *Bitcask) Delete(key []byte) error {
 		b.mu.Unlock()
 		return err
 	}
+	if item, found := b.trie.Search(key); found {
+		b.metadata.ReclaimableSpace += item.(internal.Item).Size + codec.MetaInfoSize + int64(len(key))
+	}
 	b.trie.Delete(key)
 	b.mu.Unlock()
 
 	return nil
 }
 
+// DeleteAll deletes all the keys. If an I/O error occurs the error is returned.
+func (b *Bitcask) DeleteAll() (err error) {
+	b.mu.RLock()
+	defer b.mu.RUnlock()
+
+	b.trie.ForEach(func(node art.Node) bool {
+		_, _, err = b.put(node.Key(), []byte{})
+		if err != nil {
+			return false
+		}
+		item, _ := b.trie.Search(node.Key())
+		b.metadata.ReclaimableSpace += item.(internal.Item).Size + codec.MetaInfoSize + int64(len(node.Key()))
+		return true
+	})
+	b.trie = art.New()
+
+	return
+}
+
 // Scan performs a prefix scan of keys matching the given prefix and calling
 // the function `f` with the keys found. If the function returns an error
 // no further keys are processed and the first error returned.
@@ -251,6 +314,7 @@ func (b *Bitcask) Fold(f func(key []byte) error) (err error) {
 	return
 }
 
+// put inserts a new (key, value). Both key and value are valid inputs.
 func (b *Bitcask) put(key, value []byte) (int64, int64, error) {
 	size := b.curr.Size()
 	if size >= int64(b.config.MaxDatafileSize) {
@@ -261,7 +325,7 @@ func (b *Bitcask) put(key, value []byte) (int64, int64, error) {
 
 		id := b.curr.FileID()
 
-		df, err := data.NewDatafile(b.path, id, true, b.config.MaxKeySize, b.config.MaxValueSize)
+		df, err := data.NewDatafile(b.path, id, true, b.config.MaxKeySize, b.config.MaxValueSize, b.config.FileFileModeBeforeUmask)
 		if err != nil {
 			return -1, 0, err
 		}
@@ -269,32 +333,68 @@ func (b *Bitcask) put(key, value []byte) (int64, int64, error) {
 		b.datafiles[id] = df
 
 		id = b.curr.FileID() + 1
-		curr, err := data.NewDatafile(b.path, id, false, b.config.MaxKeySize, b.config.MaxValueSize)
+		curr, err := data.NewDatafile(b.path, id, false, b.config.MaxKeySize, b.config.MaxValueSize, b.config.FileFileModeBeforeUmask)
 		if err != nil {
 			return -1, 0, err
 		}
 		b.curr = curr
+		err = b.saveIndex()
+		if err != nil {
+			return -1, 0, err
+		}
 	}
 
 	e := internal.NewEntry(key, value)
 	return b.curr.Write(e)
 }
 
-func (b *Bitcask) reopen() error {
+// closeCurrentFile closes current datafile and makes it read only.
+func (b *Bitcask) closeCurrentFile() error {
+	err := b.curr.Close()
+	if err != nil {
+		return err
+	}
+	id := b.curr.FileID()
+	df, err := data.NewDatafile(b.path, id, true, b.config.MaxKeySize, b.config.MaxValueSize, b.config.FileFileModeBeforeUmask)
+	if err != nil {
+		return err
+	}
+
+	b.datafiles[id] = df
+	return nil
+}
+
+// openNewWritableFile opens new datafile for writing data
+func (b *Bitcask) openNewWritableFile() error {
+	id := b.curr.FileID() + 1
+	curr, err := data.NewDatafile(b.path, id, false, b.config.MaxKeySize, b.config.MaxValueSize, b.config.FileFileModeBeforeUmask)
+	if err != nil {
+		return err
+	}
+	b.curr = curr
+	return nil
+}
+
+func (b *Bitcask) Reopen() error {
 	b.mu.Lock()
 	defer b.mu.Unlock()
 
-	datafiles, lastID, err := loadDatafiles(b.path, b.config.MaxKeySize, b.config.MaxValueSize)
+	return b.reopen()
+}
+
+// reopen reloads a bitcask object with index and datafiles
+// caller of this method should take care of locking
+func (b *Bitcask) reopen() error {
+	datafiles, lastID, err := loadDatafiles(b.path, b.config.MaxKeySize, b.config.MaxValueSize, b.config.FileFileModeBeforeUmask)
+	if err != nil {
+		return err
+	}
+	t, err := loadIndex(b.path, b.indexer, b.config.MaxKeySize, datafiles, lastID, b.metadata.IndexUpToDate)
 	if err != nil {
 		return err
 	}
 
-	t, err := loadIndex(b.path, b.indexer, b.config.MaxKeySize, datafiles)
-	if err != nil {
-		return err
-	}
-
-	curr, err := data.NewDatafile(b.path, lastID, false, b.config.MaxKeySize, b.config.MaxValueSize)
+	curr, err := data.NewDatafile(b.path, lastID, false, b.config.MaxKeySize, b.config.MaxValueSize, b.config.FileFileModeBeforeUmask)
 	if err != nil {
 		return err
 	}
@@ -310,6 +410,34 @@ func (b *Bitcask) reopen() error {
 // and deleted keys removes. Duplicate key/value pairs are also removed.
 // Call this function periodically to reclaim disk space.
 func (b *Bitcask) Merge() error {
+	b.mu.Lock()
+	if b.isMerging {
+		b.mu.Unlock()
+		return ErrMergeInProgress
+	}
+	b.isMerging = true
+	b.mu.Unlock()
+	defer func() {
+		b.isMerging = false
+	}()
+	b.mu.RLock()
+	err := b.closeCurrentFile()
+	if err != nil {
+		b.mu.RUnlock()
+		return err
+	}
+	filesToMerge := make([]int, 0, len(b.datafiles))
+	for k := range b.datafiles {
+		filesToMerge = append(filesToMerge, k)
+	}
+	err = b.openNewWritableFile()
+	if err != nil {
+		b.mu.RUnlock()
+		return err
+	}
+	b.mu.RUnlock()
+	sort.Ints(filesToMerge)
+
 	// Temporary merged database path
 	temp, err := ioutil.TempDir(b.path, "merge")
 	if err != nil {
@@ -318,7 +446,7 @@ func (b *Bitcask) Merge() error {
 	defer os.RemoveAll(temp)
 
 	// Create a merged database
-	mdb, err := Open(temp, b.options...)
+	mdb, err := Open(temp, withConfig(b.config))
 	if err != nil {
 		return err
 	}
@@ -327,7 +455,12 @@ func (b *Bitcask) Merge() error {
 	// Doing this automatically strips deleted keys and
 	// old key/value pairs
 	err = b.Fold(func(key []byte) error {
-		value, err := b.Get(key)
+		item, _ := b.trie.Search(key)
+		// if key was updated after start of merge operation, nothing to do
+		if item.(internal.Item).FileID > filesToMerge[len(filesToMerge)-1] {
+			return nil
+		}
+		value, err := b.get(key)
 		if err != nil {
 			return err
 		}
@@ -341,29 +474,36 @@ func (b *Bitcask) Merge() error {
 	if err != nil {
 		return err
 	}
-
-	err = mdb.Close()
-	if err != nil {
+	if err = mdb.Close(); err != nil {
+		return err
+	}
+	// no reads and writes till we reopen
+	b.mu.Lock()
+	defer b.mu.Unlock()
+	if err = b.close(); err != nil {
 		return err
 	}
 
-	// Close the database
-	err = b.Close()
-	if err != nil {
-		return err
-	}
-
-	// Remove all data files
+	// Remove data files
 	files, err := ioutil.ReadDir(b.path)
 	if err != nil {
 		return err
 	}
 	for _, file := range files {
-		if !file.IsDir() {
-			err := os.RemoveAll(path.Join([]string{b.path, file.Name()}...))
-			if err != nil {
-				return err
-			}
+		if file.IsDir() {
+			continue
+		}
+		ids, err := internal.ParseIds([]string{file.Name()})
+		if err != nil {
+			return err
+		}
+		// if datafile was created after start of merge, skip
+		if len(ids) > 0 && ids[0] > filesToMerge[len(filesToMerge)-1] {
+			continue
+		}
+		err = os.RemoveAll(path.Join(b.path, file.Name()))
+		if err != nil {
+			return err
 		}
 	}
 
@@ -381,6 +521,7 @@ func (b *Bitcask) Merge() error {
 			return err
 		}
 	}
+	b.metadata.ReclaimableSpace = 0
 
 	// And finally reopen the database
 	return b.reopen()
@@ -391,14 +532,11 @@ func (b *Bitcask) Merge() error {
 // configuration options as functions.
 func Open(path string, options ...Option) (*Bitcask, error) {
 	var (
-		cfg *config.Config
-		err error
+		cfg  *config.Config
+		err  error
+		meta *metadata.MetaData
 	)
 
-	if err := os.MkdirAll(path, 0755); err != nil {
-		return nil, err
-	}
-
 	configPath := filepath.Join(path, "config.json")
 	if internal.Exists(configPath) {
 		cfg, err = config.Load(configPath)
@@ -409,20 +547,30 @@ func Open(path string, options ...Option) (*Bitcask, error) {
 		cfg = newDefaultConfig()
 	}
 
-	bitcask := &Bitcask{
-		Flock:   flock.New(filepath.Join(path, "lock")),
-		config:  cfg,
-		options: options,
-		path:    path,
-		indexer: index.NewIndexer(),
-	}
-
 	for _, opt := range options {
-		if err := opt(bitcask.config); err != nil {
+		if err := opt(cfg); err != nil {
 			return nil, err
 		}
 	}
 
+	if err := os.MkdirAll(path, cfg.DirFileModeBeforeUmask); err != nil {
+		return nil, err
+	}
+
+	meta, err = loadMetadata(path)
+	if err != nil {
+		return nil, err
+	}
+
+	bitcask := &Bitcask{
+		Flock:    flock.New(filepath.Join(path, "lock")),
+		config:   cfg,
+		options:  options,
+		path:     path,
+		indexer:  index.NewIndexer(),
+		metadata: meta,
+	}
+
 	locked, err := bitcask.Flock.TryLock()
 	if err != nil {
 		return nil, err
@@ -436,14 +584,49 @@ func Open(path string, options ...Option) (*Bitcask, error) {
 		return nil, err
 	}
 
-	if err := bitcask.reopen(); err != nil {
+	if cfg.AutoRecovery {
+		if err := data.CheckAndRecover(path, cfg); err != nil {
+			return nil, fmt.Errorf("recovering database: %s", err)
+		}
+	}
+	if err := bitcask.Reopen(); err != nil {
 		return nil, err
 	}
 
 	return bitcask, nil
 }
 
-func loadDatafiles(path string, maxKeySize uint32, maxValueSize uint64) (datafiles map[int]data.Datafile, lastID int, err error) {
+// Backup copies db directory to given path
+// it creates path if it does not exist
+func (b *Bitcask) Backup(path string) error {
+	if !internal.Exists(path) {
+		if err := os.MkdirAll(path, b.config.DirFileModeBeforeUmask); err != nil {
+			return err
+		}
+	}
+	return internal.Copy(b.path, path, []string{"lock"})
+}
+
+// saveIndex saves index currently in RAM to disk
+func (b *Bitcask) saveIndex() error {
+	tempIdx := "temp_index"
+	if err := b.indexer.Save(b.trie, filepath.Join(b.path, tempIdx)); err != nil {
+		return err
+	}
+	return os.Rename(filepath.Join(b.path, tempIdx), filepath.Join(b.path, "index"))
+}
+
+// saveMetadata saves metadata into disk
+func (b *Bitcask) saveMetadata() error {
+	return b.metadata.Save(filepath.Join(b.path, "meta.json"), b.config.DirFileModeBeforeUmask)
+}
+
+// Reclaimable returns space that can be reclaimed
+func (b *Bitcask) Reclaimable() int64 {
+	return b.metadata.ReclaimableSpace
+}
+
+func loadDatafiles(path string, maxKeySize uint32, maxValueSize uint64, fileModeBeforeUmask os.FileMode) (datafiles map[int]data.Datafile, lastID int, err error) {
 	fns, err := internal.GetDatafiles(path)
 	if err != nil {
 		return nil, 0, err
@@ -456,7 +639,7 @@ func loadDatafiles(path string, maxKeySize uint32, maxValueSize uint64) (datafil
 
 	datafiles = make(map[int]data.Datafile, len(ids))
 	for _, id := range ids {
-		datafiles[id], err = data.NewDatafile(path, id, true, maxKeySize, maxValueSize)
+		datafiles[id], err = data.NewDatafile(path, id, true, maxKeySize, maxValueSize, fileModeBeforeUmask)
 		if err != nil {
 			return
 		}
@@ -468,34 +651,69 @@ func loadDatafiles(path string, maxKeySize uint32, maxValueSize uint64) (datafil
 	return
 }
 
-func loadIndex(path string, indexer index.Indexer, maxKeySize uint32, datafiles map[int]data.Datafile) (art.Tree, error) {
+func getSortedDatafiles(datafiles map[int]data.Datafile) []data.Datafile {
+	out := make([]data.Datafile, len(datafiles))
+	idx := 0
+	for _, df := range datafiles {
+		out[idx] = df
+		idx++
+	}
+	sort.Slice(out, func(i, j int) bool {
+		return out[i].FileID() < out[j].FileID()
+	})
+	return out
+}
+
+func loadIndex(path string, indexer index.Indexer, maxKeySize uint32, datafiles map[int]data.Datafile, lastID int, indexUpToDate bool) (art.Tree, error) {
 	t, found, err := indexer.Load(filepath.Join(path, "index"), maxKeySize)
 	if err != nil {
 		return nil, err
 	}
-	if !found {
-		for _, df := range datafiles {
-			var offset int64
-			for {
-				e, n, err := df.Read()
-				if err != nil {
-					if err == io.EOF {
-						break
-					}
-					return nil, err
-				}
-
-				// Tombstone value  (deleted key)
-				if len(e.Value) == 0 {
-					t.Delete(e.Key)
-					offset += n
-					continue
-				}
-				item := internal.Item{FileID: df.FileID(), Offset: offset, Size: n}
-				t.Insert(e.Key, item)
-				offset += n
-			}
+	if found && indexUpToDate {
+		return t, nil
+	}
+	if found {
+		if err := loadIndexFromDatafile(t, datafiles[lastID]); err != nil {
+			return nil, err
+		}
+		return t, nil
+	}
+	sortedDatafiles := getSortedDatafiles(datafiles)
+	for _, df := range sortedDatafiles {
+		if err := loadIndexFromDatafile(t, df); err != nil {
+			return nil, err
 		}
 	}
 	return t, nil
 }
+
+func loadIndexFromDatafile(t art.Tree, df data.Datafile) error {
+	var offset int64
+	for {
+		e, n, err := df.Read()
+		if err != nil {
+			if err == io.EOF {
+				break
+			}
+			return err
+		}
+		// Tombstone value  (deleted key)
+		if len(e.Value) == 0 {
+			t.Delete(e.Key)
+			offset += n
+			continue
+		}
+		item := internal.Item{FileID: df.FileID(), Offset: offset, Size: n}
+		t.Insert(e.Key, item)
+		offset += n
+	}
+	return nil
+}
+
+func loadMetadata(path string) (*metadata.MetaData, error) {
+	if !internal.Exists(filepath.Join(path, "meta.json")) {
+		meta := new(metadata.MetaData)
+		return meta, nil
+	}
+	return metadata.Load(filepath.Join(path, "meta.json"))
+}

bitcask_test.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"io/ioutil"
 	"os"
+	"path"
 	"path/filepath"
 	"reflect"
 	"sort"
@@ -14,6 +15,7 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 
 	"github.com/prologic/bitcask/internal"
 	"github.com/prologic/bitcask/internal/config"
@@ -127,12 +129,113 @@ func TestAll(t *testing.T) {
 		assert.NoError(err)
 	})
 
+	t.Run("Backup", func(t *testing.T) {
+		path, err := ioutil.TempDir("", "backup")
+		defer os.RemoveAll(path)
+		assert.NoError(err)
+		err = db.Backup(filepath.Join(path, "db-backup"))
+		assert.NoError(err)
+	})
+
 	t.Run("Close", func(t *testing.T) {
 		err = db.Close()
 		assert.NoError(err)
 	})
 }
 
+func TestDeleteAll(t *testing.T) {
+	assert := assert.New(t)
+	testdir, _ := ioutil.TempDir("", "bitcask")
+	db, _ := Open(testdir)
+	_ = db.Put([]byte("foo"), []byte("foo"))
+	_ = db.Put([]byte("bar"), []byte("bar"))
+	_ = db.Put([]byte("baz"), []byte("baz"))
+	assert.Equal(3, db.Len())
+	err := db.DeleteAll()
+	assert.NoError(err)
+	assert.Equal(0, db.Len())
+	_, err = db.Get([]byte("foo"))
+	assert.Equal(ErrKeyNotFound, err)
+	_, err = db.Get([]byte("bar"))
+	assert.Equal(ErrKeyNotFound, err)
+	_, err = db.Get([]byte("baz"))
+	assert.Equal(ErrKeyNotFound, err)
+}
+
+func TestReopen1(t *testing.T) {
+	assert := assert.New(t)
+	for i := 0; i < 10; i++ {
+		testdir, _ := ioutil.TempDir("", "bitcask")
+		db, _ := Open(testdir, WithMaxDatafileSize(1))
+		_ = db.Put([]byte("foo"), []byte("bar"))
+		_ = db.Put([]byte("foo"), []byte("bar1"))
+		_ = db.Put([]byte("foo"), []byte("bar2"))
+		_ = db.Put([]byte("foo"), []byte("bar3"))
+		_ = db.Put([]byte("foo"), []byte("bar4"))
+		_ = db.Put([]byte("foo"), []byte("bar5"))
+		_ = db.Reopen()
+		val, _ := db.Get([]byte("foo"))
+		assert.Equal("bar5", string(val))
+	}
+}
+
+func TestReopen(t *testing.T) {
+	assert := assert.New(t)
+
+	testdir, err := ioutil.TempDir("", "bitcask")
+	assert.NoError(err)
+
+	t.Run("Reopen", func(t *testing.T) {
+		var (
+			db  *Bitcask
+			err error
+		)
+
+		t.Run("Open", func(t *testing.T) {
+			db, err = Open(testdir)
+			assert.NoError(err)
+		})
+
+		t.Run("Put", func(t *testing.T) {
+			err = db.Put([]byte("foo"), []byte("bar"))
+			assert.NoError(err)
+		})
+
+		t.Run("Get", func(t *testing.T) {
+			val, err := db.Get([]byte("foo"))
+			assert.NoError(err)
+			assert.Equal([]byte("bar"), val)
+		})
+
+		t.Run("Reopen", func(t *testing.T) {
+			err = db.Reopen()
+			assert.NoError(err)
+		})
+
+		t.Run("GetAfterReopen", func(t *testing.T) {
+			val, err := db.Get([]byte("foo"))
+			assert.NoError(err)
+			assert.Equal([]byte("bar"), val)
+		})
+
+		t.Run("PutAfterReopen", func(t *testing.T) {
+			err = db.Put([]byte("zzz"), []byte("foo"))
+			assert.NoError(err)
+		})
+
+		t.Run("GetAfterReopenAndPut", func(t *testing.T) {
+			val, err := db.Get([]byte("zzz"))
+			assert.NoError(err)
+			assert.Equal([]byte("foo"), val)
+		})
+
+		t.Run("Close", func(t *testing.T) {
+			err = db.Close()
+			assert.NoError(err)
+		})
+	})
+}
+
 func TestDeletedKeys(t *testing.T) {
 	assert := assert.New(t)
 
@@ -204,6 +307,64 @@ func TestDeletedKeys(t *testing.T) {
 	})
 }
 
+func TestMetadata(t *testing.T) {
+	assert := assert.New(t)
+	testdir, err := ioutil.TempDir("", "bitcask")
+	assert.NoError(err)
+	defer os.RemoveAll(testdir)
+
+	db, err := Open(testdir)
+	assert.NoError(err)
+	err = db.Put([]byte("foo"), []byte("bar"))
+	assert.NoError(err)
+	err = db.Close()
+	assert.NoError(err)
+	db, err = Open(testdir)
+	assert.NoError(err)
+
+	t.Run("IndexUptoDateAfterCloseAndOpen", func(t *testing.T) {
+		assert.Equal(true, db.metadata.IndexUpToDate)
+	})
+	t.Run("IndexUptoDateAfterPut", func(t *testing.T) {
+		assert.NoError(db.Put([]byte("foo1"), []byte("bar1")))
+		assert.Equal(false, db.metadata.IndexUpToDate)
+	})
+	t.Run("Reclaimable", func(t *testing.T) {
+		assert.Equal(int64(0), db.Reclaimable())
+	})
+	t.Run("ReclaimableAfterNewPut", func(t *testing.T) {
+		assert.NoError(db.Put([]byte("hello"), []byte("world")))
+		assert.Equal(int64(0), db.Reclaimable())
+	})
+	t.Run("ReclaimableAfterRepeatedPut", func(t *testing.T) {
+		assert.NoError(db.Put([]byte("hello"), []byte("world")))
+		assert.Equal(int64(26), db.Reclaimable())
+	})
+	t.Run("ReclaimableAfterDelete", func(t *testing.T) {
+		assert.NoError(db.Delete([]byte("hello")))
+		assert.Equal(int64(73), db.Reclaimable())
+	})
+	t.Run("ReclaimableAfterNonExistingDelete", func(t *testing.T) {
+		assert.NoError(db.Delete([]byte("hello1")))
+		assert.Equal(int64(73), db.Reclaimable())
+	})
+	t.Run("ReclaimableAfterDeleteAll", func(t *testing.T) {
+		assert.NoError(db.DeleteAll())
+		assert.Equal(int64(158), db.Reclaimable())
+	})
+	t.Run("ReclaimableAfterMerge", func(t *testing.T) {
+		assert.NoError(db.Merge())
+		assert.Equal(int64(0), db.Reclaimable())
+	})
+	t.Run("IndexUptoDateAfterMerge", func(t *testing.T) {
+		assert.Equal(true, db.metadata.IndexUpToDate)
+	})
+	t.Run("ReclaimableAfterMergeAndDeleteAll", func(t *testing.T) {
+		assert.NoError(db.DeleteAll())
+		assert.Equal(int64(0), db.Reclaimable())
+	})
+}
+
 func TestConfigErrors(t *testing.T) {
 	assert := assert.New(t)
 
@@ -234,6 +395,82 @@ func TestConfigErrors(t *testing.T) {
 	})
 }
 
+func TestAutoRecovery(t *testing.T) {
+	withAutoRecovery := []bool{false, true}
+
+	for _, autoRecovery := range withAutoRecovery {
+		t.Run(fmt.Sprintf("%v", autoRecovery), func(t *testing.T) {
+			require := require.New(t)
+			testdir, err := ioutil.TempDir("", "bitcask")
+			require.NoError(err)
+			db, err := Open(testdir)
+			require.NoError(err)
+
+			// Insert 10 key-value pairs and verify all is ok.
+			makeKeyVal := func(i int) ([]byte, []byte) {
+				return []byte(fmt.Sprintf("foo%d", i)), []byte(fmt.Sprintf("bar%d", i))
+			}
+			n := 10
+			for i := 0; i < n; i++ {
+				key, val := makeKeyVal(i)
+				err = db.Put(key, val)
+				require.NoError(err)
+			}
+			for i := 0; i < n; i++ {
+				key, val := makeKeyVal(i)
+				rval, err := db.Get(key)
+				require.NoError(err)
+				require.Equal(val, rval)
+			}
+			err = db.Close()
+			require.NoError(err)
+
+			// Corrupt the last inserted key
+			f, err := os.OpenFile(path.Join(testdir, "000000000.data"), os.O_RDWR, 0755)
+			require.NoError(err)
+			fi, err := f.Stat()
+			require.NoError(err)
+			err = f.Truncate(fi.Size() - 1)
+			require.NoError(err)
+			err = f.Close()
+			require.NoError(err)
+
+			db, err = Open(testdir, WithAutoRecovery(autoRecovery))
+			require.NoError(err)
+			defer db.Close()
+			// Check that all values but the last are still intact.
+			for i := 0; i < 9; i++ {
+				key, val := makeKeyVal(i)
+				rval, err := db.Get(key)
+				require.NoError(err)
+				require.Equal(val, rval)
+			}
+			// Check the index has no more keys than non-corrupted ones.
+			// i.e: all but the last one.
+			numKeys := 0
+			for range db.Keys() {
+				numKeys++
+			}
+			if !autoRecovery {
+				// We are opening without autorepair, and thus are
+				// in a corrupted state. The index isn't coherent with
+				// the datafile.
+				require.Equal(n, numKeys)
+				return
+			}
+
+			require.Equal(n-1, numKeys, "The index should have n-1 keys")
+
+			// Double-check explicitly the corrupted one isn't here.
+			// This check is redundant considering the last two checks,
+			// but doesn't hurt.
+			corrKey, _ := makeKeyVal(9)
+			_, err = db.Get(corrKey)
+			require.Equal(ErrKeyNotFound, err)
+		})
+	}
+}
+
 func TestReIndex(t *testing.T) {
 	assert := assert.New(t)
 
@@ -396,6 +633,11 @@ func TestSync(t *testing.T) {
 		value := []byte("foobar")
 		err = db.Put(key, value)
 	})
+
+	t.Run("Put", func(t *testing.T) {
+		err = db.Put([]byte("hello"), []byte("world"))
+		assert.NoError(err)
+	})
 }
 
 func TestMaxKeySize(t *testing.T) {
@@ -523,7 +765,9 @@ func TestStatsError(t *testing.T) {
 			assert.Equal(stats.Datafiles, 0)
 			assert.Equal(stats.Keys, 1)
 		})
+	})
 
+	t.Run("Test", func(t *testing.T) {
 		t.Run("FabricatedDestruction", func(t *testing.T) {
 			// This would never happen in reality :D
 			// Or would it? :)
@@ -538,6 +782,162 @@ func TestStatsError(t *testing.T) {
 	})
 }
 
+func TestDirFileModeBeforeUmask(t *testing.T) {
+	assert := assert.New(t)
+
+	t.Run("Setup", func(t *testing.T) {
+		t.Run("Default DirFileModeBeforeUmask is 0700", func(t *testing.T) {
+			testdir, err := ioutil.TempDir("", "bitcask")
+			embeddedDir := filepath.Join(testdir, "cache")
+			assert.NoError(err)
+			defer os.RemoveAll(testdir)
+
+			defaultTestMode := os.FileMode(0700)
+
+			db, err := Open(embeddedDir)
+			assert.NoError(err)
+			defer db.Close()
+			err = filepath.Walk(testdir, func(path string, info os.FileInfo, err error) error {
+				// skip the root directory
+				if path == testdir {
+					return nil
+				}
+				if info.IsDir() {
+					// perms for directory on disk are filtered through defaultTestMode, AND umask of user running test.
+					// this means the mkdir calls can only FURTHER restrict permissions, not grant more (preventing escalatation).
+					// to make this test OS agnostic, we'll skip using golang.org/x/sys/unix, inferring umask via XOR and AND NOT.
+
+					// create anotherDir with allPerms - to infer umask
+					anotherDir := filepath.Join(testdir, "temp")
+					err := os.Mkdir(anotherDir, os.ModePerm)
+					assert.NoError(err)
+					defer os.RemoveAll(anotherDir)
+
+					anotherStat, err := os.Stat(anotherDir)
+					assert.NoError(err)
+
+					// infer umask from anotherDir
+					umask := os.ModePerm ^ (anotherStat.Mode() & os.ModePerm)
+
+					assert.Equal(info.Mode()&os.ModePerm, defaultTestMode&^umask)
+				}
+				return nil
+			})
+			assert.NoError(err)
+		})
+
+		t.Run("Dir FileModeBeforeUmask is set via options for all subdirectories", func(t *testing.T) {
+			testdir, err := ioutil.TempDir("", "bitcask")
+			embeddedDir := filepath.Join(testdir, "cache")
+			assert.NoError(err)
+			defer os.RemoveAll(testdir)
+
+			testMode := os.FileMode(0713)
+
+			db, err := Open(embeddedDir, WithDirFileModeBeforeUmask(testMode))
+			assert.NoError(err)
+			defer db.Close()
+			err = filepath.Walk(testdir, func(path string, info os.FileInfo, err error) error {
+				// skip the root directory
+				if path == testdir {
+					return nil
+				}
+				if info.IsDir() {
+					// create anotherDir with allPerms - to infer umask
+					anotherDir := filepath.Join(testdir, "temp")
+					err := os.Mkdir(anotherDir, os.ModePerm)
+					assert.NoError(err)
+					defer os.RemoveAll(anotherDir)
+
+					anotherStat, _ := os.Stat(anotherDir)
+
+					// infer umask from anotherDir
+					umask := os.ModePerm ^ (anotherStat.Mode() & os.ModePerm)
+
+					assert.Equal(info.Mode()&os.ModePerm, testMode&^umask)
+				}
+				return nil
+			})
+			assert.NoError(err)
+		})
+
+	})
+}
+
+func TestFileFileModeBeforeUmask(t *testing.T) {
+	assert := assert.New(t)
+
+	t.Run("Setup", func(t *testing.T) {
+		t.Run("Default File FileModeBeforeUmask is 0600", func(t *testing.T) {
+			testdir, err := ioutil.TempDir("", "bitcask")
+			assert.NoError(err)
+			defer os.RemoveAll(testdir)
+
+			defaultTestMode := os.FileMode(0600)
+
+			db, err := Open(testdir)
+			assert.NoError(err)
+			defer db.Close()
+			err = filepath.Walk(testdir, func(path string, info os.FileInfo, err error) error {
+				if !info.IsDir() {
+					// the lock file is set within Flock, so ignore it
+					if filepath.Base(path) == "lock" {
+						return nil
+					}
+					// create aFile with allPerms - to infer umask
+					aFilePath := filepath.Join(testdir, "temp")
+					_, err := os.OpenFile(aFilePath, os.O_CREATE, os.ModePerm)
+					assert.NoError(err)
+					defer os.RemoveAll(aFilePath)
+
+					fileStat, _ := os.Stat(aFilePath)
+
+					// infer umask from anotherDir
+					umask := os.ModePerm ^ (fileStat.Mode() & os.ModePerm)
+
+					assert.Equal(info.Mode()&os.ModePerm, defaultTestMode&^umask)
+				}
+				return nil
+			})
+			assert.NoError(err)
+		})
+
+		t.Run("File FileModeBeforeUmask is set via options for all files", func(t *testing.T) {
+			testdir, err := ioutil.TempDir("", "bitcask")
+			assert.NoError(err)
+			defer os.RemoveAll(testdir)
+
+			testMode := os.FileMode(0673)
+
+			db, err := Open(testdir, WithFileFileModeBeforeUmask(testMode))
+			assert.NoError(err)
+			defer db.Close()
+			err = filepath.Walk(testdir, func(path string, info os.FileInfo, err error) error {
+				if !info.IsDir() {
+					// the lock file is set within Flock, so ignore it
+					if filepath.Base(path) == "lock" {
+						return nil
+					}
+					// create aFile with allPerms - to infer umask
+					aFilePath := filepath.Join(testdir, "temp")
+					_, err := os.OpenFile(aFilePath, os.O_CREATE, os.ModePerm)
+					assert.NoError(err)
+					defer os.RemoveAll(aFilePath)
+
+					fileStat, _ := os.Stat(aFilePath)
+
+					// infer umask from anotherDir
+					umask := os.ModePerm ^ (fileStat.Mode() & os.ModePerm)
+
+					assert.Equal(info.Mode()&os.ModePerm, testMode&^umask)
+				}
+				return nil
+			})
+			assert.NoError(err)
+		})
+	})
+}
+
 func TestMaxDatafileSize(t *testing.T) {
 	var (
 		db  *Bitcask
@@ -639,7 +1039,7 @@ func TestMerge(t *testing.T) {
 
 		s3, err := db.Stats()
 		assert.NoError(err)
-		assert.Equal(1, s3.Datafiles)
+		assert.Equal(2, s3.Datafiles)
 		assert.Equal(1, s3.Keys)
 		assert.True(s3.Size > s1.Size)
 		assert.True(s3.Size < s2.Size)
@@ -714,6 +1114,24 @@ func TestGetErrors(t *testing.T) {
 
 }
 
+func TestPutBorderCases(t *testing.T) {
+	assert := assert.New(t)
+
+	t.Run("EmptyValue", func(t *testing.T) {
+		testdir, err := ioutil.TempDir("", "bitcask")
+		assert.NoError(err)
+
+		db, err := Open(testdir)
+		assert.NoError(err)
+
+		err = db.Put([]byte("alice"), nil)
+		assert.NoError(err)
+		z, err := db.Get([]byte("alice"))
+		assert.NoError(err)
+		assert.Empty(z)
+	})
+}
+
 func TestPutErrors(t *testing.T) {
 	assert := assert.New(t)
 
@@ -766,6 +1184,18 @@ func TestPutErrors(t *testing.T) {
 		assert.Error(err)
 		assert.Equal(ErrMockError, err)
 	})
+
+	t.Run("EmptyKey", func(t *testing.T) {
+		testdir, err := ioutil.TempDir("", "bitcask")
+		assert.NoError(err)
+
+		db, err := Open(testdir)
+		assert.NoError(err)
+		err = db.Put(nil, []byte("hello"))
+		assert.Equal(ErrEmptyKey, err)
+
+	})
+
 }
 
 func TestOpenErrors(t *testing.T) {
@@ -833,7 +1263,7 @@ func TestCloseErrors(t *testing.T) {
 		assert.NoError(err)
 
 		mockIndexer := new(mocks.Indexer)
-		mockIndexer.On("Save", db.trie, filepath.Join(db.path, "index")).Return(ErrMockError)
+		mockIndexer.On("Save", db.trie, filepath.Join(db.path, "temp_index")).Return(ErrMockError)
 		db.indexer = mockIndexer
 
 		err = db.Close()
@@ -939,18 +1369,19 @@ func TestMergeErrors(t *testing.T) {
 		assert.NoError(err)
 		defer os.RemoveAll(testdir)
 
-		db, err := Open(testdir)
+		db, err := Open(testdir, WithMaxDatafileSize(22))
 		assert.NoError(err)
 
 		assert.NoError(db.Put([]byte("foo"), []byte("bar")))
+		assert.NoError(db.Put([]byte("bar"), []byte("baz")))
 
 		mockDatafile := new(mocks.Datafile)
-		mockDatafile.On("FileID").Return(0)
+		mockDatafile.On("Close").Return(nil)
 		mockDatafile.On("ReadAt", int64(0), int64(22)).Return(
 			internal.Entry{},
 			ErrMockError,
 		)
-		db.curr = mockDatafile
+		db.datafiles[0] = mockDatafile
 
 		err = db.Merge()
 		assert.Error(err)
@@ -999,11 +1430,11 @@ func TestConcurrent(t *testing.T) {
 			}
 
 			wg := &sync.WaitGroup{}
+			wg.Add(3)
 
 			go f(wg, 2)
 			go f(wg, 3)
 			go f(wg, 5)
-			wg.Add(3)
 
 			wg.Wait()
 		})
@@ -1021,15 +1452,100 @@ func TestConcurrent(t *testing.T) {
 			}
 
 			wg := &sync.WaitGroup{}
-
-			go f(wg, 100)
-			go f(wg, 100)
-			go f(wg, 100)
 			wg.Add(3)
+			go f(wg, 100)
+			go f(wg, 100)
+			go f(wg, 100)
 
 			wg.Wait()
 		})
 
+		// Test concurrent Put() with concurrent Scan()
+		t.Run("PutScan", func(t *testing.T) {
+			doPut := func(wg *sync.WaitGroup, x int) {
+				defer func() {
+					wg.Done()
+				}()
+				for i := 0; i <= 100; i++ {
+					if i%x == 0 {
+						key := []byte(fmt.Sprintf("k%d", i))
+						value := []byte(fmt.Sprintf("v%d", i))
+						err := db.Put(key, value)
+						assert.NoError(err)
+					}
+				}
+			}
+
+			doScan := func(wg *sync.WaitGroup, x int) {
+				defer func() {
+					wg.Done()
+				}()
+				for i := 0; i <= 100; i++ {
+					if i%x == 0 {
+						err := db.Scan([]byte("k"), func(key []byte) error {
+							return nil
+						})
+						assert.NoError(err)
+					}
+				}
+			}
+
+			wg := &sync.WaitGroup{}
+			wg.Add(6)
+
+			go doPut(wg, 2)
+			go doPut(wg, 3)
+			go doPut(wg, 5)
+			go doScan(wg, 1)
+			go doScan(wg, 2)
+			go doScan(wg, 4)
+
+			wg.Wait()
+		})
+
+		// XXX: This has data races
+		/* Test concurrent Scan() with concurrent Merge()
+		t.Run("ScanMerge", func(t *testing.T) {
+			doScan := func(wg *sync.WaitGroup, x int) {
+				defer func() {
+					wg.Done()
+				}()
+				for i := 0; i <= 100; i++ {
+					if i%x == 0 {
+						err := db.Scan([]byte("k"), func(key []byte) error {
+							return nil
+						})
+						assert.NoError(err)
+					}
+				}
+			}
+
+			doMerge := func(wg *sync.WaitGroup, x int) {
+				defer func() {
+					wg.Done()
+				}()
+				for i := 0; i <= 100; i++ {
+					if i%x == 0 {
+						err := db.Merge()
+						assert.NoError(err)
+					}
+				}
+			}
+
+			wg := &sync.WaitGroup{}
+			wg.Add(6)
+
+			go doScan(wg, 2)
+			go doScan(wg, 3)
+			go doScan(wg, 5)
+			go doMerge(wg, 1)
+			go doMerge(wg, 2)
+			go doMerge(wg, 4)
+
+			wg.Wait()
+		})
+		*/
+
 		t.Run("Close", func(t *testing.T) {
 			err = db.Close()
 			assert.NoError(err)
@@ -1109,7 +1625,6 @@ func TestLocking(t *testing.T) {
 
 	_, err = Open(testdir)
 	assert.Error(err)
-	assert.Equal(ErrDatabaseLocked, err)
 }
 
 type benchmarkTestCase struct {

cmd/bitcaskd/main.go

@@ -55,5 +55,7 @@ func main() {
 		os.Exit(2)
 	}
 
-	log.Fatal(server.Run())
+	if err = server.Run(); err != nil {
+		log.Fatal(err)
+	}
 }

cmd/bitcaskd/server.go

@@ -2,7 +2,10 @@ package main
 
 import (
 	"fmt"
+	"os"
+	"os/signal"
 	"strings"
+	"syscall"
 
 	log "github.com/sirupsen/logrus"
 	"github.com/tidwall/redcon"
@@ -35,6 +38,14 @@ func (s *server) handleSet(cmd redcon.Command, conn redcon.Conn) {
 	}
 	key := cmd.Args[1]
 	value := cmd.Args[2]
+
+	err := s.db.Lock()
+	if err != nil {
+		conn.WriteError("ERR " + fmt.Errorf("failed to lock db: %v", err).Error() + "")
+		return
+	}
+	defer s.db.Unlock()
+
 	if err := s.db.Put(key, value); err != nil {
 		conn.WriteString(fmt.Sprintf("ERR: %s", err))
 	} else {
@@ -47,7 +58,16 @@ func (s *server) handleGet(cmd redcon.Command, conn redcon.Conn) {
 		conn.WriteError("ERR wrong number of arguments for '" + string(cmd.Args[0]) + "' command")
 		return
 	}
+
 	key := cmd.Args[1]
+
+	err := s.db.Lock()
+	if err != nil {
+		conn.WriteError("ERR " + fmt.Errorf("failed to lock db: %v", err).Error() + "")
+		return
+	}
+	defer s.db.Unlock()
+
 	value, err := s.db.Get(key)
 	if err != nil {
 		conn.WriteNull()
@@ -57,9 +77,16 @@ func (s *server) handleGet(cmd redcon.Command, conn redcon.Conn) {
 }
 
 func (s *server) handleKeys(cmd redcon.Command, conn redcon.Conn) {
+	err := s.db.Lock()
+	if err != nil {
+		conn.WriteError("ERR " + fmt.Errorf("failed to lock db: %v", err).Error() + "")
+		return
+	}
+	defer s.db.Unlock()
+
 	conn.WriteArray(s.db.Len())
 	for key := range s.db.Keys() {
-		conn.WriteBulk([]byte(key))
+		conn.WriteBulk(key)
 	}
 }
 
@@ -68,7 +95,16 @@ func (s *server) handleExists(cmd redcon.Command, conn redcon.Conn) {
 		conn.WriteError("ERR wrong number of arguments for '" + string(cmd.Args[0]) + "' command")
 		return
 	}
+
 	key := cmd.Args[1]
+
+	err := s.db.Lock()
+	if err != nil {
+		conn.WriteError("ERR " + fmt.Errorf("failed to lock db: %v", err).Error() + "")
+		return
+	}
+	defer s.db.Unlock()
+
 	if s.db.Has(key) {
 		conn.WriteInt(1)
 	} else {
@@ -81,7 +117,16 @@ func (s *server) handleDel(cmd redcon.Command, conn redcon.Conn) {
 		conn.WriteError("ERR wrong number of arguments for '" + string(cmd.Args[0]) + "' command")
 		return
 	}
+
 	key := cmd.Args[1]
+
+	err := s.db.Lock()
+	if err != nil {
+		conn.WriteError("ERR " + fmt.Errorf("failed to lock db: %v", err).Error() + "")
+		return
+	}
+	defer s.db.Unlock()
+
 	if err := s.db.Delete(key); err != nil {
 		conn.WriteInt(0)
 	} else {
@@ -89,8 +134,13 @@ func (s *server) handleDel(cmd redcon.Command, conn redcon.Conn) {
 	}
 }
 
+func (s *server) Shutdown() (err error) {
+	err = s.db.Close()
+	return
+}
+
 func (s *server) Run() (err error) {
-	err = redcon.ListenAndServe(s.bind,
+	redServer := redcon.NewServerNetwork("tcp", s.bind,
 		func(conn redcon.Conn, cmd redcon.Command) {
 			switch strings.ToLower(string(cmd.Args[0])) {
 			case "ping":
@@ -118,5 +168,17 @@ func (s *server) Run() (err error) {
 		func(conn redcon.Conn, err error) {
 		},
 	)
+
+	go func() {
+		signals := make(chan os.Signal, 1)
+		signal.Notify(signals, os.Interrupt, syscall.SIGTERM)
+		s := <-signals
+		log.Infof("Shutdown server on signal %s", s)
+		redServer.Close()
+	}()
+
+	if err := redServer.ListenAndServe(); err == nil {
+		return s.Shutdown()
+	}
 	return
 }

flock/flock.go

@@ -0,0 +1,97 @@
+package flock
+
+import (
+	"errors"
+	"os"
+	"sync"
+)
+
+type Flock struct {
+	path string
+	m    sync.Mutex
+	fh   *os.File
+}
+
+var (
+	ErrAlreadyLocked = errors.New("Double lock: already own the lock")
+	ErrLockFailed    = errors.New("Could not acquire lock")
+	ErrLockNotHeld   = errors.New("Could not unlock, lock is not held")
+
+	ErrInodeChangedAtPath = errors.New("Inode changed at path")
+)
+
+// New returns a new instance of *Flock. The only parameter
+// it takes is the path to the desired lockfile.
+func New(path string) *Flock {
+	return &Flock{path: path}
+}
+
+// Path returns the file path linked to this lock.
+func (f *Flock) Path() string {
+	return f.path
+}
+
+// Lock will acquire the lock. This function may block indefinitely if some other process holds the lock. For a non-blocking version, see Flock.TryLock().
+func (f *Flock) Lock() error {
+	f.m.Lock()
+	defer f.m.Unlock()
+
+	if f.fh != nil {
+		return ErrAlreadyLocked
+	}
+
+	var fh *os.File
+
+	fh, err := lock_sys(f.path, false)
+	// treat "ErrInodeChangedAtPath" as "some other process holds the lock, retry locking"
+	for err == ErrInodeChangedAtPath {
+		fh, err = lock_sys(f.path, false)
+	}
+
+	if err != nil {
+		return err
+	}
+	if fh == nil {
+		return ErrLockFailed
+	}
+
+	f.fh = fh
+	return nil
+}
+
+// TryLock will try to acquire the lock, and returns immediately if the lock is already owned by another process.
+func (f *Flock) TryLock() (bool, error) {
+	f.m.Lock()
+	defer f.m.Unlock()
+
+	if f.fh != nil {
+		return false, ErrAlreadyLocked
+	}
+
+	fh, err := lock_sys(f.path, true)
+	if err != nil {
+		return false, ErrLockFailed
+	}
+
+	f.fh = fh
+	return true, nil
+}
+
+// Unlock removes the lock file from disk and releases the lock.
+// Whatever the result of `.Unlock()`, the caller must assume that it does not hold the lock anymore.
+func (f *Flock) Unlock() error {
+	f.m.Lock()
+	defer f.m.Unlock()
+
+	if f.fh == nil {
+		return ErrLockNotHeld
+	}
+
+	err1 := rm_if_match(f.fh, f.path)
+	err2 := f.fh.Close()
+
+	if err1 != nil {
+		return err1
+	}
+	return err2
+}

flock/flock_test.go

@@ -0,0 +1,121 @@
+package flock
+
+import (
+	"os"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+// WARNING : this test will delete the file located at "testLockPath". Choose an adequate temporary file name.
+const testLockPath = "/tmp/bitcask_unit_test_lock" // file path to use for the lock
+
+func TestTryLock(t *testing.T) {
+	// test that basic locking functionnalities are consistent
+
+	// make sure there is no present lock when startng this test
+	os.Remove(testLockPath)
+
+	assert := assert.New(t)
+
+	lock1 := New(testLockPath)
+	lock2 := New(testLockPath)
+
+	// 1- take the first lock
+	locked1, err := lock1.TryLock()
+	assert.True(locked1)
+	assert.NoError(err)
+
+	// 2- check that the second lock cannot acquire the lock
+	locked2, err := lock2.TryLock()
+	assert.False(locked2)
+	assert.Error(err)
+
+	// 3- release the first lock
+	err = lock1.Unlock()
+	assert.NoError(err)
+
+	// 4- check that the second lock can acquire and then release the lock without error
+	locked2, err = lock2.TryLock()
+	assert.True(locked2)
+	assert.NoError(err)
+
+	err = lock2.Unlock()
+	assert.NoError(err)
+}
+
+func TestLock(t *testing.T) {
+	assert := assert.New(t)
+
+	// make sure there is no present lock when startng this test
+	os.Remove(testLockPath)
+
+	syncChan := make(chan bool)
+
+	// main goroutine: take lock on testPath
+	lock := New(testLockPath)
+
+	err := lock.Lock()
+	assert.NoError(err)
+
+	go func() {
+		// sub routine:
+		lock := New(testLockPath)
+
+		// before entering the block '.Lock()' call, signal we are about to do it
+		// see below : the main goroutine will wait for a small delay before releasing the lock
+		syncChan <- true
+		// '.Lock()' should ultimately return without error :
+		err := lock.Lock()
+		assert.NoError(err)
+
+		err = lock.Unlock()
+		assert.NoError(err)
+
+		close(syncChan)
+	}()
+
+	// wait for the "ready" signal from the sub routine,
+	<-syncChan
+
+	// after that signal wait for a small delay before releasing the lock
+	<-time.After(100 * time.Microsecond)
+	err = lock.Unlock()
+	assert.NoError(err)
+
+	// wait for the sub routine to finish
+	<-syncChan
+}
+
+func TestErrorConditions(t *testing.T) {
+	// error conditions implemented in this version :
+	// - you can't release a lock you do not hold
+	// - you can't lock twice the same lock
+
+	// -- setup
+	assert := assert.New(t)
+
+	// make sure there is no present lock when startng this test
+	os.Remove(testLockPath)
+
+	lock := New(testLockPath)
+
+	// -- run tests :
+
+	err := lock.Unlock()
+	assert.Error(err, "you can't release a lock you do not hold")
+
+	// take the lock once:
+	lock.TryLock()
+
+	locked, err := lock.TryLock()
+	assert.False(locked)
+	assert.Error(err, "you can't lock twice the same lock (using .TryLock())")
+
+	err = lock.Lock()
+	assert.Error(err, "you can't lock twice the same lock (using .Lock())")
+
+	// -- teardown
+	lock.Unlock()
+}

flock/flock_unix.go

@@ -0,0 +1,79 @@
+// +build !aix,!windows
+
+package flock
+
+import (
+	"os"
+
+	"golang.org/x/sys/unix"
+)
+
+func lock_sys(path string, nonBlocking bool) (_ *os.File, err error) {
+	var fh *os.File
+
+	fh, err = os.OpenFile(path, os.O_RDWR|os.O_CREATE, 0666)
+	if err != nil {
+		return nil, err
+	}
+
+	defer func() {
+		if err != nil {
+			fh.Close()
+		}
+	}()
+
+	flag := unix.LOCK_EX
+	if nonBlocking {
+		flag |= unix.LOCK_NB
+	}
+
+	err = unix.Flock(int(fh.Fd()), flag)
+	if err != nil {
+		return nil, err
+	}
+
+	if !sameInodes(fh, path) {
+		return nil, ErrInodeChangedAtPath
+	}
+
+	return fh, nil
+}
+
+func rm_if_match(fh *os.File, path string) error {
+	// Sanity check :
+	// before running "rm", check that the file pointed at by the
+	// filehandle has the same inode as the path in the filesystem
+	//
+	// If this sanity check doesn't pass, store a "ErrInodeChangedAtPath" error,
+	// if the check passes, run os.Remove, and store the error if any.
+	//
+	// note : this sanity check is in no way atomic, but :
+	//   - as long as only cooperative processes are involved, it will work as intended
+	//   - it allows to avoid 99.9% the major pitfall case: "root user forcefully removed the lockfile"
+
+	if !sameInodes(fh, path) {
+		return ErrInodeChangedAtPath
+	}
+
+	return os.Remove(path)
+}
+
+func sameInodes(f *os.File, path string) bool {
+	// get inode from opened file f:
+	var fstat unix.Stat_t
+	err := unix.Fstat(int(f.Fd()), &fstat)
+	if err != nil {
+		return false
+	}
+	fileIno := fstat.Ino
+
+	// get inode for path on disk:
+	var dstat unix.Stat_t
+	err = unix.Stat(path, &dstat)
+	if err != nil {
+		return false
+	}
+	pathIno := dstat.Ino
+
+	return pathIno == fileIno
+}

flock/race_test.go

@@ -0,0 +1,236 @@
+package flock
+
+// the "nd" in "nd_test.go" stands for non-deterministic
+
+import (
+	"errors"
+	"os"
+	"sync"
+	"sync/atomic"
+	"syscall"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+// The two tests in this file are test some concurrency scenarios :
+// 1- TestRaceLock() runs several threads racing for the same lock
+// 2- TestShatteredLock() runs racing racing threads, along with another threads which forcibly remove the file from disk
+//
+// Note that these tests are non-deterministic : the coverage produced by each test depends
+// on how the runtime chooses to schedule the concurrent goroutines.
+
+var lockerCount int64
+
+// lockAndCount tries to take a lock on "lockpath"
+// if it fails : it returns 0 and stop there
+// if it succeeds :
+//   1- it sets a defer function to release the lock in the same fashion as "func (b *Bitcask) Close()"
+//   2- it increments the shared "lockerCount" above
+//   3- it waits for a short amount of time
+//   4- it decrements "lockerCount"
+//   5- it returns the value it has seen at step 2.
+//
+// If the locking and unlocking behave as we expect them to,
+// instructions 1-5 should be in a critical section,
+// and the only possible value at step 2 should be "1".
+//
+// Returning a value > 0 indicates this function successfully acquired the lock,
+// returning a value == 0 indicates that TryLock failed.
+
+func lockAndCount(lockpath string) int64 {
+	lock := New(lockpath)
+	ok, _ := lock.TryLock()
+	if !ok {
+		return 0
+	}
+	defer func() {
+		lock.Unlock()
+	}()
+
+	x := atomic.AddInt64(&lockerCount, 1)
+	// emulate a workload :
+	<-time.After(1 * time.Microsecond)
+	atomic.AddInt64(&lockerCount, -1)
+
+	return x
+}
+
+// locker will call the lock function above in a loop, until one of the following holds :
+//  - reading from the "timeout" channel doesn't block
+//  - the number of calls to "lock()" that indicate the lock was successfully taken reaches "successfullLockCount"
+func locker(t *testing.T, id int, lockPath string, successfulLockCount int, timeout <-chan struct{}) {
+	timedOut := false
+
+	failCount := 0
+	max := int64(0)
+
+lockloop:
+	for successfulLockCount > 0 {
+		select {
+		case <-timeout:
+			timedOut = true
+			break lockloop
+		default:
+		}
+
+		x := lockAndCount(lockPath)
+
+		if x > 0 {
+			// if x indicates the lock was taken : decrement the counter
+			successfulLockCount--
+		}
+
+		if x > 1 {
+			// if x indicates an invalid value : increase the failCount and update max accordingly
+			failCount++
+			if x > max {
+				max = x
+			}
+		}
+	}
+
+	// check failure cases :
+	if timedOut {
+		t.Fail()
+		t.Logf("[runner %02d] timed out", id)
+	}
+	if failCount > 0 {
+		t.Fail()
+		t.Logf("[runner %02d] lockCounter was > 1 on %2.d occasions, max seen value was %2.d", id, failCount, max)
+	}
+}
+
+// TestRaceLock checks that no error occurs when several concurrent actors (goroutines in this case) race for the same lock.
+func TestRaceLock(t *testing.T) {
+	// test parameters, written in code :
+	//   you may want to tweak these values for testing
+
+	goroutines := 20          // number of concurrent "locker" goroutines to launch
+	successfulLockCount := 50 // how many times a "locker" will successfully take the lock before halting
+
+	// make sure there is no present lock when startng this test
+	os.Remove(testLockPath)
+
+	// timeout implemented in code
+	// (the lock acquisition depends on the behavior of the filesystem,
+	//	avoid sending CI in endless loop if something fishy happens on the test server ...)
+	// tweak this value if needed ; comment out the "close(ch)" instruction below
+	timeout := 10 * time.Second
+	ch := make(chan struct{})
+	go func() {
+		<-time.After(timeout)
+		close(ch)
+	}()
+
+	wg := &sync.WaitGroup{}
+	wg.Add(goroutines)
+
+	for i := 0; i < goroutines; i++ {
+		go func(id int) {
+			locker(t, id, testLockPath, successfulLockCount, ch)
+			wg.Done()
+		}(i)
+	}
+
+	wg.Wait()
+}
+
+func isExpectedError(err error) bool {
+	switch {
+	case err == nil:
+		return true
+	case err == ErrInodeChangedAtPath:
+		return true
+	case errors.Is(err, syscall.ENOENT):
+		return true
+
+	default:
+		return false
+	}
+}
+
+// TestShatteredLock runs concurrent goroutines on one lock, with an extra goroutine
+// which removes the lock file from disk without checking the locks
+// (e.g: a user who would run 'rm lockfile' in a loop while the program is running).
+//
+// In this scenario, errors may occur on .Unlock() ; this test checks that only errors
+// relating to the file being deleted occur.
+//
+// This test additionally logs the number of errors that occurred, grouped by error message.
+func TestShatteredLock(t *testing.T) {
+	// test parameters, written in code :
+	//   you may want to tweak these values for testing
+
+	goroutines := 4           // number of concurrent "locker" and "remover" goroutines to launch
+	successfulLockCount := 10 // how many times a "locker" will successfully take the lock before halting
+
+	// make sure there is no present lock when startng this test
+	os.Remove(testLockPath)
+	assert := assert.New(t)
+
+	wg := &sync.WaitGroup{}
+	wg.Add(goroutines)
+
+	stopChan := make(chan struct{})
+
+	errChan := make(chan error, 10)
+
+	for i := 0; i < goroutines; i++ {
+		go func(id int, count int) {
+			for count > 0 {
+				lock := New(testLockPath)
+				ok, _ := lock.TryLock()
+				if !ok {
+					continue
+				}
+
+				count--
+				err := lock.Unlock()
+				if !isExpectedError(err) {
+					assert.Fail("goroutine %d - unexpected error: %v", id, err)
+				}
+
+				if err != nil {
+					errChan <- err
+				}
+			}
+
+			wg.Done()
+		}(i, successfulLockCount)
+	}
+
+	var wgCompanion = &sync.WaitGroup{}
+	wgCompanion.Add(2)
+
+	go func() {
+		defer wgCompanion.Done()
+		for {
+			os.Remove(testLockPath)
+
+			select {
+			case <-stopChan:
+				return
+			default:
+			}
+		}
+	}()
+
+	var errs = make(map[string]int)
+	go func() {
+		for err := range errChan {
+			errs[err.Error()]++
+		}
+		wgCompanion.Done()
+	}()
+
+	wg.Wait()
+	close(stopChan)
+	close(errChan)
+	wgCompanion.Wait()
+
+	for err, count := range errs {
+		t.Logf("  seen %d times: %s", count, err)
+	}
+}

go.mod

@@ -3,21 +3,21 @@ module github.com/prologic/bitcask
 go 1.13
 
 require (
-	github.com/gofrs/flock v0.7.1
-	github.com/konsorten/go-windows-terminal-sequences v1.0.2 // indirect
-	github.com/magiconair/properties v1.8.1 // indirect
-	github.com/pelletier/go-toml v1.4.0 // indirect
-	github.com/pkg/errors v0.8.1
-	github.com/plar/go-adaptive-radix-tree v1.0.1
-	github.com/sirupsen/logrus v1.4.2
+	github.com/pelletier/go-toml v1.6.0 // indirect
+	github.com/pkg/errors v0.9.1
+	github.com/plar/go-adaptive-radix-tree v1.0.4
+	github.com/sirupsen/logrus v1.7.0
 	github.com/spf13/afero v1.2.2 // indirect
-	github.com/spf13/cobra v0.0.5
+	github.com/spf13/cast v1.3.1 // indirect
+	github.com/spf13/cobra v0.0.7
 	github.com/spf13/jwalterweatherman v1.1.0 // indirect
-	github.com/spf13/pflag v1.0.3
-	github.com/spf13/viper v1.4.0
-	github.com/stretchr/testify v1.3.0
-	github.com/tidwall/redcon v1.0.0
-	golang.org/x/exp v0.0.0-20190731235908-ec7cb31e5a56
-	golang.org/x/sys v0.0.0-20190804053845-51ab0e2deafa // indirect
-	golang.org/x/text v0.3.2 // indirect
+	github.com/spf13/pflag v1.0.5
+	github.com/spf13/viper v1.7.1
+	github.com/stretchr/objx v0.2.0 // indirect
+	github.com/stretchr/testify v1.6.1
+	github.com/tidwall/redcon v1.4.0
+	golang.org/x/exp v0.0.0-20200228211341-fcea875c7e85
+	golang.org/x/sys v0.0.0-20200302150141-5c8b2ff67527
+	gopkg.in/ini.v1 v1.53.0 // indirect
+	gopkg.in/yaml.v2 v2.3.0 // indirect
 )

go.sum

@@ -1,87 +1,153 @@
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+cloud.google.com/go v0.38.0/go.mod h1:990N+gfupTy94rShfmMCWGDn0LpTmnzTp2qbd1dvSRU=
+cloud.google.com/go v0.44.1/go.mod h1:iSa0KzasP4Uvy3f1mN/7PiObzGgflwredwwASm/v6AU=
+cloud.google.com/go v0.44.2/go.mod h1:60680Gw3Yr4ikxnPRS/oxxkBccT6SA1yMk63TGekxKY=
+cloud.google.com/go v0.45.1/go.mod h1:RpBamKRgapWJb87xiFSdk4g1CME7QZg3uwTez+TSTjc=
+cloud.google.com/go v0.46.3/go.mod h1:a6bKKbmY7er1mI7TEI4lsAkts/mkhTSZK8w33B4RAg0=
+cloud.google.com/go/bigquery v1.0.1/go.mod h1:i/xbL2UlR5RvWAURpBYZTtm/cXjCha9lbfbpx4poX+o=
+cloud.google.com/go/datastore v1.0.0/go.mod h1:LXYbyblFSglQ5pkeyhO+Qmw7ukd3C+pD7TKLgZqpHYE=
+cloud.google.com/go/firestore v1.1.0/go.mod h1:ulACoGHTpvq5r8rxGJ4ddJZBZqakUQqClKRT5SZwBmk=
+cloud.google.com/go/pubsub v1.0.1/go.mod h1:R0Gpsv3s54REJCy4fxDixWD93lHJMoZTyQ2kNxGRt3I=
+cloud.google.com/go/storage v1.0.0/go.mod h1:IhtSnM/ZTZV8YYJWCY8RULGVqBDmpoyjwiyrjsg+URw=
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+google.golang.org/genproto v0.0.0-20190425155659-357c62f0e4bb/go.mod h1:VzzqZJRnGkLBvHegQrXjBqPurQTc5/KpmUdxsrq26oE=
+google.golang.org/genproto v0.0.0-20190502173448-54afdca5d873/go.mod h1:VzzqZJRnGkLBvHegQrXjBqPurQTc5/KpmUdxsrq26oE=
+google.golang.org/genproto v0.0.0-20190801165951-fa694d86fc64/go.mod h1:DMBHOl98Agz4BDEuKkezgsaosCRResVns1a3J2ZsMNc=
+google.golang.org/genproto v0.0.0-20190819201941-24fa4b261c55/go.mod h1:DMBHOl98Agz4BDEuKkezgsaosCRResVns1a3J2ZsMNc=
+google.golang.org/genproto v0.0.0-20190911173649-1774047e7e51/go.mod h1:IbNlFCBrqXvoKpeg0TB2l7cyZUmoaFKYIwrEpbDKLA8=
+google.golang.org/genproto v0.0.0-20191108220845-16a3f7862a1a/go.mod h1:n3cpQtvxv34hfy77yVDNjmbRyujviMdxYliBSkLhpCc=
 google.golang.org/grpc v1.19.0/go.mod h1:mqu4LbDTu4XGKhr4mRzUsmM4RtVoemTSY81AxZiDr8c=
+google.golang.org/grpc v1.20.1/go.mod h1:10oTOabMzJvdu6/UiuZezV6QK5dSlG84ov/aaiqXj38=
 google.golang.org/grpc v1.21.0/go.mod h1:oYelfM1adQP15Ek0mdvEgi9Df8B9CZIaU1084ijfRaM=
+google.golang.org/grpc v1.21.1/go.mod h1:oYelfM1adQP15Ek0mdvEgi9Df8B9CZIaU1084ijfRaM=
 gopkg.in/alecthomas/kingpin.v2 v2.2.6/go.mod h1:FMv+mEhP44yOT+4EoQTLFTRgOQ1FBLkstjWtayDeSgw=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 h1:qIbj1fsPNlZgppZ+VLlY7N33q108Sa+fhmuc+sWQYwY=
 gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/errgo.v2 v2.1.0/go.mod h1:hNsd1EY+bozCKY1Ytp96fpM3vjJbqLJn88ws8XvfDNI=
+gopkg.in/ini.v1 v1.51.0/go.mod h1:pNLf8WUiyNEtQjuu5G5vTm06TEv9tsIgeAvK8hOrP4k=
+gopkg.in/ini.v1 v1.53.0 h1:c7ruDvTQi0MUTFuNpDRXLSjs7xT4TerM1icIg4uKWRg=
+gopkg.in/ini.v1 v1.53.0/go.mod h1:pNLf8WUiyNEtQjuu5G5vTm06TEv9tsIgeAvK8hOrP4k=
 gopkg.in/resty.v1 v1.12.0/go.mod h1:mDo4pnntr5jdWRML875a/NmxYqAlA73dVijT2AXvQQo=
 gopkg.in/yaml.v2 v2.0.0-20170812160011-eb3733d160e7/go.mod h1:JAlM8MvJe8wmxCU4Bli9HhUf9+ttbYbLASfIpnQbh74=
 gopkg.in/yaml.v2 v2.2.1/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
-gopkg.in/yaml.v2 v2.2.2 h1:ZCJp+EgiOT7lHqUV2J862kp8Qj64Jo6az82+3Td9dZw=
 gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v2 v2.2.4/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v2 v2.3.0 h1:clyUAQHOM3G0M3f5vQj7LuJrETvjVot3Z5el9nffUtU=
+gopkg.in/yaml.v2 v2.3.0/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 honnef.co/go/tools v0.0.0-20190102054323-c2f93a96b099/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
+honnef.co/go/tools v0.0.0-20190106161140-3f1c8253044a/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
+honnef.co/go/tools v0.0.0-20190418001031-e561f6794a2a/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
+honnef.co/go/tools v0.0.1-2019.2.3/go.mod h1:a3bituU0lyd329TUQxRnasdCoJDkEUEAqEt0JzvZhAg=
+rsc.io/binaryregexp v0.2.0/go.mod h1:qTv7/COck+e2FymRvadv62gMdZztPaShugOCi3I+8D8=

internal/config/config.go

@@ -8,10 +8,13 @@ import (
 
 // Config contains the bitcask configuration parameters
 type Config struct {
-	MaxDatafileSize int    `json:"max_datafile_size"`
-	MaxKeySize      uint32 `json:"max_key_size"`
-	MaxValueSize    uint64 `json:"max_value_size"`
-	Sync            bool   `json:"sync"`
+	MaxDatafileSize         int    `json:"max_datafile_size"`
+	MaxKeySize              uint32 `json:"max_key_size"`
+	MaxValueSize            uint64 `json:"max_value_size"`
+	Sync                    bool   `json:"sync"`
+	AutoRecovery            bool   `json:"autorecovery"`
+	DirFileModeBeforeUmask  os.FileMode
+	FileFileModeBeforeUmask os.FileMode
 }
 
 // Load loads a configuration from the given path
@@ -32,23 +35,16 @@ func Load(path string) (*Config, error) {
 
 // Save saves the configuration to the provided path
 func (c *Config) Save(path string) error {
-	f, err := os.OpenFile(path, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0600)
-	if err != nil {
-		return err
-	}
 
 	data, err := json.Marshal(c)
 	if err != nil {
 		return err
 	}
 
-	if _, err = f.Write(data); err != nil {
+	err = ioutil.WriteFile(path, data, c.FileFileModeBeforeUmask)
+	if err != nil {
 		return err
 	}
 
-	if err = f.Sync(); err != nil {
-		return err
-	}
-
-	return f.Close()
+	return nil
 }

internal/data/codec/decoder.go

@@ -74,7 +74,7 @@ func getKeyValueSizes(buf []byte, maxKeySize uint32, maxValueSize uint64) (uint3
 	actualKeySize := binary.BigEndian.Uint32(buf[:keySize])
 	actualValueSize := binary.BigEndian.Uint64(buf[keySize:])
 
-	if actualKeySize > maxKeySize || actualValueSize > maxValueSize || actualKeySize == 0 {
+	if (maxKeySize > 0 && actualKeySize > maxKeySize) || (maxValueSize > 0 && actualValueSize > maxValueSize) || actualKeySize == 0 {
 
 		return 0, 0, errInvalidKeyOrValueSize
 	}

internal/data/codec/encoder.go

@@ -13,6 +13,7 @@ const (
 	keySize      = 4
 	valueSize    = 8
 	checksumSize = 4
+	MetaInfoSize = keySize + valueSize + checksumSize
 )
 
 // NewEncoder creates a streaming Entry encoder.

internal/data/datafile.go

@@ -19,8 +19,6 @@ const (
 var (
 	errReadonly  = errors.New("error: read only datafile")
 	errReadError = errors.New("error: read error")
-
-	mxMemPool sync.RWMutex
 )
 
 // Datafile is an interface  that represents a readable and writeable datafile
@@ -50,7 +48,7 @@ type datafile struct {
 }
 
 // NewDatafile opens an existing datafile
-func NewDatafile(path string, id int, readonly bool, maxKeySize uint32, maxValueSize uint64) (Datafile, error) {
+func NewDatafile(path string, id int, readonly bool, maxKeySize uint32, maxValueSize uint64, fileMode os.FileMode) (Datafile, error) {
 	var (
 		r   *os.File
 		ra  *mmap.ReaderAt
@@ -61,7 +59,7 @@ func NewDatafile(path string, id int, readonly bool, maxKeySize uint32, maxValue
 	fn := filepath.Join(path, fmt.Sprintf(defaultDatafileFilename, id))
 
 	if !readonly {
-		w, err = os.OpenFile(fn, os.O_WRONLY|os.O_APPEND|os.O_CREATE, 0640)
+		w, err = os.OpenFile(fn, os.O_WRONLY|os.O_APPEND|os.O_CREATE, fileMode)
 		if err != nil {
 			return nil, err
 		}

internal/data/recover.go

@@ -0,0 +1,95 @@
+package data
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+
+	"github.com/prologic/bitcask/internal"
+	"github.com/prologic/bitcask/internal/config"
+	"github.com/prologic/bitcask/internal/data/codec"
+)
+
+// CheckAndRecover checks and recovers the last datafile.
+// If the datafile isn't corrupted, this is a noop. If it is,
+// the longest non-corrupted prefix will be kept and the rest
+// will be *deleted*. Also, the index file is also *deleted* which
+// will be automatically recreated on next startup.
+func CheckAndRecover(path string, cfg *config.Config) error {
+	dfs, err := internal.GetDatafiles(path)
+	if err != nil {
+		return fmt.Errorf("scanning datafiles: %s", err)
+	}
+	if len(dfs) == 0 {
+		return nil
+	}
+	f := dfs[len(dfs)-1]
+	recovered, err := recoverDatafile(f, cfg)
+	if err != nil {
+		return fmt.Errorf("recovering data file")
+	}
+	if recovered {
+		if err := os.Remove(filepath.Join(path, "index")); err != nil {
+			return fmt.Errorf("error deleting the index on recovery: %s", err)
+		}
+	}
+	return nil
+}
+
+func recoverDatafile(path string, cfg *config.Config) (recovered bool, err error) {
+	f, err := os.Open(path)
+	if err != nil {
+		return false, fmt.Errorf("opening the datafile: %s", err)
+	}
+	defer func() {
+		closeErr := f.Close()
+		if err == nil {
+			err = closeErr
+		}
+	}()
+	_, file := filepath.Split(path)
+	rPath := fmt.Sprintf("%s.recovered", file)
+	fr, err := os.OpenFile(rPath, os.O_CREATE|os.O_WRONLY, os.ModePerm)
+	if err != nil {
+		return false, fmt.Errorf("creating the recovered datafile: %w", err)
+	}
+	defer func() {
+		closeErr := fr.Close()
+		if err == nil {
+			err = closeErr
+		}
+	}()
+
+	dec := codec.NewDecoder(f, cfg.MaxKeySize, cfg.MaxValueSize)
+	enc := codec.NewEncoder(fr)
+	e := internal.Entry{}
+
+	corrupted := false
+	for !corrupted {
+		_, err = dec.Decode(&e)
+		if err == io.EOF {
+			break
+		}
+		if codec.IsCorruptedData(err) {
+			corrupted = true
+			continue
+		}
+		if err != nil {
+			return false, fmt.Errorf("unexpected error while reading datafile: %w", err)
+		}
+		if _, err := enc.Encode(e); err != nil {
+			return false, fmt.Errorf("writing to recovered datafile: %w", err)
+		}
+	}
+	if !corrupted {
+		if err := os.Remove(fr.Name()); err != nil {
+			return false, fmt.Errorf("can't remove temporal recovered datafile: %w", err)
+		}
+		return false, nil
+	}
+	if err := os.Rename(rPath, path); err != nil {
+		return false, fmt.Errorf("removing corrupted file: %s", err)
+	}
+	return true, nil
+}

internal/index/codec_index.go

@@ -34,7 +34,7 @@ func readKeyBytes(r io.Reader, maxKeySize uint32) ([]byte, error) {
 		return nil, errors.Wrap(errTruncatedKeySize, err.Error())
 	}
 	size := binary.BigEndian.Uint32(s)
-	if size > uint32(maxKeySize) {
+	if maxKeySize > 0 && size > uint32(maxKeySize) {
 		return nil, errKeySizeTooLarge
 	}
 
@@ -117,11 +117,7 @@ func writeIndex(t art.Tree, w io.Writer) (err error) {
 
 		item := node.Value().(internal.Item)
 		err := writeItem(item, w)
-		if err != nil {
-			return false
-		}
-
-		return true
+		return err == nil
 	})
 	return
 }

internal/metadata/metadata.go

@@ -0,0 +1,22 @@
+package metadata
+
+import (
+	"os"
+
+	"github.com/prologic/bitcask/internal"
+)
+
+type MetaData struct {
+	IndexUpToDate    bool  `json:"index_up_to_date"`
+	ReclaimableSpace int64 `json:"reclaimable_space"`
+}
+
+func (m *MetaData) Save(path string, mode os.FileMode) error {
+	return internal.SaveJsonToFile(m, path, mode)
+}
+
+func Load(path string) (*MetaData, error) {
+	var m MetaData
+	err := internal.LoadFromJsonFile(path, &m)
+	return &m, err
+}

internal/utils.go

@@ -1,7 +1,9 @@
 package internal
 
 import (
+	"encoding/json"
 	"fmt"
+	"io/ioutil"
 	"os"
 	"path/filepath"
 	"sort"
@@ -33,7 +35,8 @@ func DirSize(path string) (int64, error) {
 
 // GetDatafiles returns a list of all data files stored in the database path
 // given by `path`. All datafiles are identified by the the glob `*.data` and
-// the basename is represented by an monotomic increasing integer.
+// the basename is represented by a monotonic increasing integer.
+// The returned files are *sorted* in increasing order.
 func GetDatafiles(path string) ([]string, error) {
 	fns, err := filepath.Glob(fmt.Sprintf("%s/*.data", path))
 	if err != nil {
@@ -62,3 +65,48 @@ func ParseIds(fns []string) ([]int, error) {
 	sort.Ints(ids)
 	return ids, nil
 }
+
+// Copy copies source contents to destination
+func Copy(src, dst string, exclude []string) error {
+	return filepath.Walk(src, func(path string, info os.FileInfo, err error) error {
+		relPath := strings.Replace(path, src, "", 1)
+		if relPath == "" {
+			return nil
+		}
+		for _, e := range exclude {
+			matched, err := filepath.Match(e, info.Name())
+			if err != nil {
+				return err
+			}
+			if matched {
+				return nil
+			}
+		}
+		if info.IsDir() {
+			return os.Mkdir(filepath.Join(dst, relPath), info.Mode())
+		}
+		var data, err1 = ioutil.ReadFile(filepath.Join(src, relPath))
+		if err1 != nil {
+			return err1
+		}
+		return ioutil.WriteFile(filepath.Join(dst, relPath), data, info.Mode())
+	})
+}
+
+// SaveJsonToFile converts v into json and store in file identified by path
+func SaveJsonToFile(v interface{}, path string, mode os.FileMode) error {
+	b, err := json.Marshal(v)
+	if err != nil {
+		return err
+	}
+	return ioutil.WriteFile(path, b, mode)
+}
+
+// LoadFromJsonFile reads file located at `path` and put its content in json format in v
+func LoadFromJsonFile(path string, v interface{}) error {
+	b, err := ioutil.ReadFile(path)
+	if err != nil {
+		return err
+	}
+	return json.Unmarshal(b, v)
+}

internal/utils_test.go

@@ -0,0 +1,108 @@
+package internal
+
+import (
+	"io"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_Copy(t *testing.T) {
+	assert := assert.New(t)
+	t.Run("CopyDir", func(t *testing.T) {
+		tempsrc, err := ioutil.TempDir("", "test")
+		assert.NoError(err)
+		defer os.RemoveAll(tempsrc)
+		var f *os.File
+
+		tempdir, err := ioutil.TempDir(tempsrc, "")
+		assert.NoError(err)
+
+		f, err = os.OpenFile(filepath.Join(tempsrc, "file1"), os.O_WRONLY|os.O_CREATE, 0755)
+		assert.NoError(err)
+		n, err := f.WriteString("test123")
+		assert.Equal(7, n)
+		assert.NoError(err)
+		f.Close()
+
+		f, err = os.OpenFile(filepath.Join(tempsrc, "file2"), os.O_WRONLY|os.O_CREATE, 0755)
+		assert.NoError(err)
+		n, err = f.WriteString("test1234")
+		assert.Equal(8, n)
+		assert.NoError(err)
+		f.Close()
+
+		f, err = os.OpenFile(filepath.Join(tempsrc, "file3"), os.O_WRONLY|os.O_CREATE, 0755)
+		assert.NoError(err)
+		f.Close()
+
+		tempdst, err := ioutil.TempDir("", "backup")
+		assert.NoError(err)
+		defer os.RemoveAll(tempdst)
+		err = Copy(tempsrc, tempdst, []string{"file3"})
+		assert.NoError(err)
+		buf := make([]byte, 10)
+
+		exists := Exists(filepath.Join(tempdst, filepath.Base(tempdir)))
+		assert.Equal(true, exists)
+
+		f, err = os.Open(filepath.Join(tempdst, "file1"))
+		assert.NoError(err)
+		n, err = f.Read(buf[:7])
+		assert.NoError(err)
+		assert.Equal(7, n)
+		assert.Equal([]byte("test123"), buf[:7])
+		_, err = f.Read(buf)
+		assert.Equal(io.EOF, err)
+		f.Close()
+
+		f, err = os.Open(filepath.Join(tempdst, "file2"))
+		assert.NoError(err)
+		n, err = f.Read(buf[:8])
+		assert.NoError(err)
+		assert.Equal(8, n)
+		assert.Equal([]byte("test1234"), buf[:8])
+		_, err = f.Read(buf)
+		assert.Equal(io.EOF, err)
+		f.Close()
+
+		exists = Exists(filepath.Join(tempdst, "file3"))
+		assert.Equal(false, exists)
+	})
+}
+
+func Test_SaveAndLoad(t *testing.T) {
+	assert := assert.New(t)
+	t.Run("save and load", func(t *testing.T) {
+		tempdir, err := ioutil.TempDir("", "bitcask")
+		assert.NoError(err)
+		defer os.RemoveAll(tempdir)
+		type test struct {
+			Value bool `json:"value"`
+		}
+		m := test{Value: true}
+		err = SaveJsonToFile(&m, filepath.Join(tempdir, "meta.json"), 0755)
+		assert.NoError(err)
+		m1 := test{}
+		err = LoadFromJsonFile(filepath.Join(tempdir, "meta.json"), &m1)
+		assert.NoError(err)
+		assert.Equal(m, m1)
+	})
+
+	t.Run("save and load error", func(t *testing.T) {
+		tempdir, err := ioutil.TempDir("", "bitcask")
+		assert.NoError(err)
+		defer os.RemoveAll(tempdir)
+		type test struct {
+			Value bool `json:"value"`
+		}
+		err = SaveJsonToFile(make(chan int), filepath.Join(tempdir, "meta.json"), 0755)
+		assert.Error(err)
+		m1 := test{}
+		err = LoadFromJsonFile(filepath.Join(tempdir, "meta.json"), &m1)
+		assert.Error(err)
+	})
+}

options.go

@@ -1,8 +1,18 @@
 package bitcask
 
-import "github.com/prologic/bitcask/internal/config"
+import (
+	"os"
+
+	"github.com/prologic/bitcask/internal/config"
+)
 
 const (
+	// DefaultDirFileModeBeforeUmask is the default os.FileMode used when creating directories
+	DefaultDirFileModeBeforeUmask = os.FileMode(0700)
+
+	// DefaultFileFileModeBeforeUmask is the default os.FileMode used when creating files
+	DefaultFileFileModeBeforeUmask = os.FileMode(0600)
+
 	// DefaultMaxDatafileSize is the default maximum datafile size in bytes
 	DefaultMaxDatafileSize = 1 << 20 // 1MB
 
@@ -14,11 +24,52 @@ const (
 
 	// DefaultSync is the default file synchronization action
 	DefaultSync = false
+
+	// DefaultAutoRecovery is the default auto-recovery action.
 )
 
 // Option is a function that takes a config struct and modifies it
 type Option func(*config.Config) error
 
+func withConfig(src *config.Config) Option {
+	return func(cfg *config.Config) error {
+		cfg.MaxDatafileSize = src.MaxDatafileSize
+		cfg.MaxKeySize = src.MaxKeySize
+		cfg.MaxValueSize = src.MaxValueSize
+		cfg.Sync = src.Sync
+		cfg.AutoRecovery = src.AutoRecovery
+		cfg.DirFileModeBeforeUmask = src.DirFileModeBeforeUmask
+		cfg.FileFileModeBeforeUmask = src.FileFileModeBeforeUmask
+		return nil
+	}
+}
+
+// WithAutoRecovery sets auto recovery of data and index file recreation.
+// IMPORTANT: This flag MUST BE used only if a proper backup was made of all
+// the existing datafiles.
+func WithAutoRecovery(enabled bool) Option {
+	return func(cfg *config.Config) error {
+		cfg.AutoRecovery = enabled
+		return nil
+	}
+}
+
+// WithDirFileModeBeforeUmask sets the FileMode used for each new file created.
+func WithDirFileModeBeforeUmask(mode os.FileMode) Option {
+	return func(cfg *config.Config) error {
+		cfg.DirFileModeBeforeUmask = mode
+		return nil
+	}
+}
+
+// WithFileFileModeBeforeUmask sets the FileMode used for each new file created.
+func WithFileFileModeBeforeUmask(mode os.FileMode) Option {
+	return func(cfg *config.Config) error {
+		cfg.FileFileModeBeforeUmask = mode
+		return nil
+	}
+}
+
 // WithMaxDatafileSize sets the maximum datafile size option
 func WithMaxDatafileSize(size int) Option {
 	return func(cfg *config.Config) error {
@@ -54,9 +105,11 @@ func WithSync(sync bool) Option {
 
 func newDefaultConfig() *config.Config {
 	return &config.Config{
-		MaxDatafileSize: DefaultMaxDatafileSize,
-		MaxKeySize:      DefaultMaxKeySize,
-		MaxValueSize:    DefaultMaxValueSize,
-		Sync:            DefaultSync,
+		MaxDatafileSize:         DefaultMaxDatafileSize,
+		MaxKeySize:              DefaultMaxKeySize,
+		MaxValueSize:            DefaultMaxValueSize,
+		Sync:                    DefaultSync,
+		DirFileModeBeforeUmask:  DefaultDirFileModeBeforeUmask,
+		FileFileModeBeforeUmask: DefaultFileFileModeBeforeUmask,
 	}
 }

tools/release.sh

@@ -1,16 +1,19 @@
-#!/bin/sh
+#!/bin/bash
 
 # Get the highest tag number
 VERSION="$(git describe --abbrev=0 --tags)"
 VERSION=${VERSION:-'0.0.0'}
 
 # Get number parts
-MAJOR="${VERSION%%.*}"; VERSION="${VERSION#*.}"
-MINOR="${VERSION%%.*}"; VERSION="${VERSION#*.}"
-PATCH="${VERSION%%.*}"; VERSION="${VERSION#*.}"
+MAJOR="${VERSION%%.*}"
+VERSION="${VERSION#*.}"
+MINOR="${VERSION%%.*}"
+VERSION="${VERSION#*.}"
+PATCH="${VERSION%%.*}"
+VERSION="${VERSION#*.}"
 
 # Increase version
-PATCH=$((PATCH+1))
+PATCH=$((PATCH + 1))
 
 TAG="${1}"
 
@@ -20,6 +23,10 @@ fi
 
 echo "Releasing ${TAG} ..."
 
+git-chglog --next-tag="${TAG}" --output CHANGELOG.md
+git commit -a -m "Update CHANGELOG for ${TAG}"
 git tag -a -s -m "Release ${TAG}" "${TAG}"
 git push --tags
-goreleaser release --rm-dist
+goreleaser release \
+  --rm-dist \
+  --release-notes <(git-chglog "${TAG}" | tail -n+5)